Pendrell 10-K 16 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 16, 2018	Jun. 30, 2017
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	PCOA
Entity Registrant Name	Pendrell Corp
Entity Central Index Key	1,359,555
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 109,412,306
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		189,109
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		53,660

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 184,482	$ 174,631
Accounts receivable	17,361	15,457
Income tax receivable, net	2,161
Other receivables	118	669
Prepaid expenses and other current assets	351	262
Total current assets	204,473	191,019
Property in service – net of accumulated depreciation of $548 and $531, respectively	44	74
Non-current accounts receivable	1,309	16,555
Other assets	29	29
Intangible assets – net of accumulated amortization of $56,224 and $61,080, respectively	2,329	4,716
Total	208,184	212,393
Current liabilities:
Accounts payable	136	125
Accrued expenses	8,797	6,278
Other liabilities	64	95
Total current liabilities	8,997	6,498
Other non-current liabilities		7,796
Total liabilities	8,997	14,294
Commitments and contingencies (Note 7)
Shareholders’ equity and noncontrolling interest:
Preferred stock, $0.01 par value, 75,000,000 shares authorized, no shares issued or outstanding		0
Additional paid-in capital	1,948,472	1,962,178
Accumulated deficit	(1,747,160)	(1,763,060)
Total Pendrell shareholders’ equity	203,973	201,806
Noncontrolling interest	(4,786)	(3,707)
Total shareholders’ equity and noncontrolling interest	199,187	198,099
Total	208,184	212,393
Class A common stock
Shareholders’ equity and noncontrolling interest:
Common stock, value	2,124	2,151
Class B common stock
Shareholders’ equity and noncontrolling interest:
Common stock, value	$ 537	$ 537

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property in service, accumulated depreciation	$ 548	$ 531
Intangible assets, accumulated amortization	$ 56,224	$ 61,080
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	75,000,000	75,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A common stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	186,927	272,682
Common stock, shares outstanding	186,927	214,913
Class B common stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	84,663	84,663
Common stock, shares outstanding	53,660	53,660

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenue		$ 42,774	$ 59,018	$ 43,519
Operating expenses:
Cost of revenues		409	18,156	10,215
Patent administration and related costs		916	1,046	2,668
Patent litigation		8,695	4,169	13,076
General and administrative		7,675	7,508	16,750
Stock-based compensation		3,422	3,424	4,507
Amortization of intangible assets		2,345	9,498	13,939
Contract termination costs		3,161
Impairment of intangible assets and goodwill				103,499
Total operating expenses		26,623	43,801	164,654
Operating income (loss)		16,151	15,217	(121,135)
Interest income		1,603	696	156
Interest expense				(53)
Gain on contingencies			2,047	6,095
Other expense		(8)	(11)	(14)
Income (loss) before income taxes		17,746	17,949	(114,951)
Income tax benefit (expense)		2,110		(2,631)
Net income (loss)		19,856	17,949	(117,582)
Net income (loss) attributable to noncontrolling interests		796	186	(7,902)
Net income (loss) attributable to Pendrell		$ 19,060	$ 17,763	$ (109,680)
Basic income (loss) per share attributable to Pendrell		$ 76.28	$ 66.38	$ (412.79)
Diluted income (loss) per share attributable to Pendrell		$ 74.22	$ 64.15	$ (412.79)
Weighted average shares outstanding:
Basic		249,866	267,589	265,707
Diluted	[1]	256,814	276,918	265,707
[1]	Stock options, restricted stock awards and units totaling 12,500, 13,053 and 27,847 for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from the calculation of diluted income (loss) per share as their inclusion was anti-dilutive.

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Class A common stock	Class B common stock	Common stock	Common stockClass A common stock	Common stockClass B common stock	Additional paid-in capital	Accumulated deficit	Shareholder's equity	Noncontrolling interests
Beginning Balance at Dec. 31, 2014	$ 289,587			$ 2,669			$ 1,952,880	$ (1,671,135)	$ 284,414	$ 5,173
Beginning Balance (in shares) at Dec. 31, 2014					212,975	53,660
Issuance of Class A common stock from exercise of stock options	219			4			215		219
Issuance of Class A common stock from exercise of stock options (in shares)					358
Class A common stock withheld at vesting to cover statutory tax obligations	(140)			(1)			(131)	(8)	(140)
Class A common stock withheld at vesting to cover statutory tax obligations (in shares)					(39)
Stock-based compensation and issuance of restricted stock, net of forfeitures	4,705			12			4,693		4,705
Stock-based compensation and issuance of restricted stock, net of forfeitures (in shares)					1,156
Repurchase of stock	(2)			(2)					(2)
Repurchase of stock, (in shares)					(250)
Shares received through divesture of Ovidian	(46)			(1)			(45)		(46)
Shares received through divesture of Ovidian (in shares)					(92)
Purchase of noncontrolling interest in Provitro Biosciences LLC	(400)						764		764	(1,164)
Net income (loss)	(117,582)							(109,680)	(109,680)	(7,902)
Ending Balance at Dec. 31, 2015	176,341			2,681			1,958,376	(1,780,823)	180,234	(3,893)
Ending Balance (in shares) at Dec. 31, 2015					214,108	53,660
Class A common stock withheld at vesting to cover statutory tax obligations	(40)						(40)		(40)
Class A common stock withheld at vesting to cover statutory tax obligations (in shares)					(63)
Stock-based compensation and issuance of restricted stock, net of forfeitures	3,849			7			3,842		3,849
Stock-based compensation and issuance of restricted stock, net of forfeitures (in shares)					868
Net income (loss)	17,949							17,763	17,763	186
Ending Balance at Dec. 31, 2016	198,099			2,688			1,962,178	(1,763,060)	201,806	(3,707)
Ending Balance (in shares) at Dec. 31, 2016		214,913	53,660		214,913	53,660
Stock-based compensation and issuance of restricted stock, net of forfeitures	3,831			1			3,830		3,831
Stock-based compensation and issuance of restricted stock, net of forfeitures (in shares)					2,692
Repurchase of stock	(19,666)			(28)			(19,638)		(19,666)
Repurchase of stock, (in shares)					(30,478)
Shares relinquished by the Liquidating Trust					(200)
Effect of accounting change to zero forfeitures for stock-based compensation							177	(177)
Sale of noncontrolling interest in subsidiary	50						1,925		1,925	(1,875)
Dividend ($12.32 per share)	(2,983)							(2,983)	(2,983)
Net income (loss)	19,856							19,060	19,060	796
Ending Balance at Dec. 31, 2017	$ 199,187			$ 2,661			$ 1,948,472	$ (1,747,160)	$ 203,973	$ (4,786)
Ending Balance (in shares) at Dec. 31, 2017		186,927	53,660		186,927	53,660

Consolidated Statements of Cha6

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical)	Dec. 31, 2017$ / shares
Common stock
Dividend per share	$ 12.32

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net income (loss) including noncontrolling interest	$ 19,856	$ 17,949	$ (117,582)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock-based compensation	3,422	3,424	4,507
Amortization of intangible assets	2,345	9,498	13,939
Impairment of intangible assets and goodwill			103,499
Depreciation	37	51	351
Non-cash cost of patents monetized			138
Loss associated with the abandonment and/or disposition of patents	41	163	958
Loss on the disposition of property			1,015
Other		4	3
Other changes in certain assets and liabilities:
Accounts receivable, current and non-current	13,342	(30,423)	44
Income tax receivable, net	(2,161)
Prepaid expenses and other current/non-current assets	(138)	91	(1,108)
Accounts payable	11	(15)	(141)
Accrued expenses and other current liabilities	(4,880)	2,388	(5,670)
Other non-current liabilities		7,796
Net cash provided by (used in) operating activities	31,875	10,926	(47)
Investing activities:
Payment received on note receivable	600	1,300
Sale of noncontrolling interest in subsidiary	50
Purchases of property in service and intangible assets	(8)	(12)	(2,077)
Proceeds associated with disposition of property			109
Net cash provided by (used in) investing activities	642	1,288	(1,968)
Financing activities:
Cash dividend paid	(2,983)
Payment of statutory taxes for stock awards	(17)	(40)	(140)
Proceeds from exercise of stock options			219
Payment of accrued obligations for purchased intangible assets			(4,000)
Purchase of noncontrolling interest in Provitro Bioscience LLC			(400)
Net cash used in financing activities	(22,666)	(40)	(4,321)
Net increase (decrease) in cash and cash equivalents	9,851	12,174	(6,336)
Cash and cash equivalents—beginning of period	174,631	162,457	168,793
Cash and cash equivalents—end of period	184,482	$ 174,631	162,457
Supplemental disclosures:
Income taxes paid	48		4,125
Supplemental disclosure of non-cash investing and financing activities:
Note receivable for disposition of property			$ 1,900
Class A common stock
Financing activities:
Repurchase of Class A common stock	$ (19,666)

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Organization and Business	1. Organization and Business Overview— These consolidated financial statements include the accounts of Pendrell Corporation (“Pendrell”) and its consolidated subsidiaries (collectively referred to as the “Company”). Since 2011, the Company’s strategy, through its consolidated subsidiaries, has been to invest in, acquire and develop businesses with unique technologies that are often protected by intellectual property (“IP”) rights, and that present the opportunity to address large, global markets. The Company’s subsidiaries focus on licensing the IP rights they hold to third parties. The Company regularly evaluates its existing investments to determine whether retention or disposition is appropriate, and investigates new investment and business acquisition opportunities. From 2011 through 2015, the Company also advised clients on various IP strategies and transactions through its consulting subsidiary Ovidian Group LLC (“Ovidian”). The Company sold Ovidian for nominal consideration in 2015. The Company was formed in 2000 to operate a next generation global mobile satellite communications system. The Company began its exit from the satellite business in 2011 and completed its exit in 2012 with (i) the sale of its medium earth orbit (“MEO”) satellite assets (“MEO Assets”) that had been in storage for nominal consideration, (ii) the transfer of its in-orbit MEO satellite to a new operator who assumed responsibility for all related operating costs effective April 1, 2012, and (iii) the deconsolidation of its MEO-related international subsidiaries.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Principles of Consolidation and Basis of Presentation— The consolidated financial statements of the Company include the assets and liabilities of its wholly-owned subsidiaries and subsidiaries it controls or in which it has a controlling financial interest. Noncontrolling interests on the consolidated balance sheets include third-party investments in entities that the Company consolidates, but does not wholly own. Noncontrolling interests are classified as part of equity and the Company allocates net income (loss), other comprehensive income (loss) and other equity transactions to its noncontrolling interests in accordance with their applicable ownership percentages. All intercompany transactions and balances have been eliminated in consolidation, including a $31.8 million loan from Pendrell to ContentGuard Holdings, Inc. (“ContentGuard”). In June 2017, the Company sold a 9% interest in ContentGuard. ContentGuard now has two minority shareholders, while Pendrell maintains an 81.1% ownership stake. In February 2015, the Company acquired the minority partner’s interest in Provitro Biosciences LLC (“Provitro”) for nominal consideration resulting in 100% ownership of Provitro. All information in these financial statements is in U.S. dollars. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Capital Structure Change— At the Company’s annual meeting of shareholders in June 2017, the Company’s shareholders approved a 1-for-100 reverse stock split of the Company’s Class A Stock and Class B common stock that was implemented on November 30, 2017 (the "2017 Reverse Split"). The 2017 Reverse Split reduced the Company’s number of record shareholders to less than 300, which allowed it to (i) terminate the Company’s Nasdaq listing, effective December 15, 2017, (ii) file to de-register the Company’s Class A Stock under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which was filed on December 26, 2017; and (iii) cease to be a reporting company under the Exchange Act after the Company’s notice of de-registration is effective, which will be no later than March 26, 2018. On September 20, 2017, the Company’s Board of Directors (the “Board”) announced that the Company does not currently plan to publish financial information following the expiration of its reporting obligations under the Exchange Act. As a result, the Company believes this Form 10-K for fiscal year ended December 31, 2017 will be its final financial statement filed with the Securities and Exchange Commission. In September 2016, the Company consummated a 1-for-10 reverse stock split (the “2016 Reverse Split”) to remediate a stock price deficiency as required by Nasdaq’s continued listing requirements. As a result of the 2017 and 2016 Reverse Splits, the share counts and per share data reported in the historical financial statements have been adjusted retrospectively as if the 2017 and 2016 Reverse Splits had been in effect for all periods presented. Additionally, the exercise prices and the number of shares issuable under the Company’s stock-based compensation plans have been adjusted retrospectively to reflect the 2017 and 2016 Reverse Splits. Segment Information— The Company operates in and reports on one segment (IP management). Operating segments are based upon the Company’s internal organization structure, how its operations are managed, and the criteria used by its Chief Operating Decision Maker. Substantially all of the Company’s revenue is generated by operations located within the United States, and the Company does not have any long-lived assets located in foreign countries. Use of Estimates— The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including among others, those related to the fair value of acquired intangible assets, the useful lives and potential impairment of intangible assets and property and equipment, the value of stock awards for the purpose of determining stock-based compensation expense, accrued liabilities (including bonus accruals), valuation allowances related to the ability to realize deferred tax assets, allowances for doubtful receivables, and certain tax liabilities. Estimates are based on historical experience and other factors, including the current economic environment as deemed appropriate under the circumstances. Estimates and assumptions are adjusted when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Any changes in estimates used to prepare these financial statements will be reflected in future periods. Cash and Cash Equivalents— Cash and cash equivalents are defined as short-term, highly liquid investments with original maturities from the date of purchase of 90 days or less. Cash and cash equivalents are comprised of the following (in thousands): December 31, 2017 2016 Cash $ 15,200 $ 13,485 Money market funds 169,282 161,146 $ 184,482 $ 174,631 The fair value of money market funds at December 31, 2017 and 2016 was classified as Level 1 in the hierarchy established by the Financial Accounting Standards Board (“FASB”) as amounts were based on quoted prices available in active markets for identical investments as of the reporting date. Accounts Receivable— Accounts receivable consist primarily of amounts billed to customers under licensing arrangements. For the years ended December 31, 2017, 2016 and 2015, the Company did not incur any losses on its accounts receivable. Based upon historical collections experience and currently available information, the Company has determined that no allowance for doubtful accounts was required at either December 31, 2017 or December 31, 2016. Carrying amounts of such receivables approximate their fair value due to their short-term nature. Prepaid Expenses and Other Current Assets— As of December 31, 2017 and 2016, prepaid expenses and other current assets consisted primarily of insurance prepayments, prepayments of patent maintenance fees and prepayments of rent for leased facilities. Property in Service— Property in service consists primarily of computer equipment, software, furniture and fixtures and leasehold improvements. Property in service is recorded at cost, net of accumulated depreciation, and is depreciated using the straight-line method. Computer equipment and furniture and fixtures are depreciated over their estimated useful lives ranging from three to five years. Software is depreciated over the shorter of its contractual license period or three years. Leasehold improvements are amortized over the shorter of their estimated useful lives or the term of the respective lease. Significant additions and improvements to property in service are capitalized. Repair and maintenance costs are expensed as incurred. Intangible Assets and Goodwill— The Company amortizes finite-lived intangible assets, including patents, acquired in purchase transactions over their expected useful lives. The Company assigns goodwill and indefinite-lived intangible assets to its reporting units based on the expected benefit from the synergies arising from each business combination. The Company evaluates finite-lived intangible assets when events or circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. These events or circumstances could include: a significant change in the business climate, legal factors, operating performance indicators, or changes in technology or customer requirements. Recoverability of an asset or asset group is measured by a comparison of the carrying amount to the future undiscounted net cash flows expected to be generated by the asset or asset group over its life. This comparison requires management to make judgments regarding estimated future cash flows. The Company’s ability to realize the estimated future cash flows may be affected by factors such as changes in operating performance, changes in business strategy, invalidation of patents, unfavorable judgments in legal proceedings and changes in economic conditions. If the Company’s estimates of the undiscounted cash flows do not equal or exceed the carrying value of the asset or asset group, an impairment charge equal to the amount by which the recorded value of the asset or asset group exceeds its fair value is recognized. The Company previously evaluated goodwill for impairment on an annual basis during the fourth quarter, or more frequently if circumstances indicated that the carrying value of a Company reporting unit may exceed its fair value. When evaluating goodwill and indefinite-lived intangible assets for impairment, the Company first performed a qualitative assessment to determine if fair value of the reporting unit was more likely than not greater than the carrying amount. If the assessment indicated that it was more likely than not that the fair value of a reporting unit was less than its carrying amount, then the Company further evaluated the estimated fair value of the reporting unit through the use of discounted cash flow models, which required management to make significant judgments as to the estimated future cash flows utilized. The Company’s ability to realize the future cash flows utilized in its fair value calculations could be affected by factors such as changes in its operating performance, changes in its business strategy, invalidation of its patents, unfavorable judgments in legal proceedings and changes in economic conditions. The results of the models were compared to the carrying amount of the reporting unit. If such comparison indicated that the fair value of the reporting unit was lower than the carrying amount, impairment would exist and the impairment charge would be measured by comparing the implied fair value of the reporting unit’s goodwill to its carrying value. During 2015, the Company determined that a portion of its intellectual property assets and the balance of its goodwill were impaired and recognized an impairment charge of $103.5 million for the year ended December 31, 2015. As a result of the impairment in 2015, the Company no longer maintains balances for goodwill or indefinite-lived intangible assets in its financial statements. Fair Value of Financial Instruments— The Company determines the fair value of its financial instruments based on the fair value hierarchy established by the FASB. The three levels of inputs used to measure fair value are as follows: Level 1—Quoted prices in active markets for identical assets and liabilities. Level 2—Quoted prices in active markets for similar assets and liabilities or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. Level 3—Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. As of December 31, 2017 and 2016, the Company’s financial instruments included its cash and cash equivalents, accounts receivable, other receivables, accounts payable and certain other assets and liabilities. The Company has determined that the carrying value of its financial instruments, based on the hierarchy established by the FASB, approximates the fair value of the financial instruments as they are equivalent to cash or due to their short-term nature. Revenue Recognition— The Company derives its operating revenue from IP monetization activities, including patent licensing and patent sales; and, in years prior to 2016, from IP consulting services. Although the Company’s revenue may occur in different forms, it regards its IP monetization activities as integrated and not separate revenue streams. For example, a third party relationship could involve consulting and licensing activities, or the acquisition of a patent portfolio can lead to licensing, consulting and patent sales revenue. The Company’s patent licensing agreements often provide for the payment of contractually determined upfront license fees representing all or a majority of the revenue that will be generated from such agreements for nonexclusive, nontransferable, limited duration licenses. These agreements typically grant (i) a nonexclusive license to make, sell, distribute, and use certain specified products that read on the Company’s patents, (ii) a covenant not to enforce patent rights against the licensee based on such activities, and (iii) the release of the licensee from certain claims. Generally, the agreements provide no further obligation for the Company upon receipt of the minimum upfront license fee. As such, the earnings process is complete and revenue is recognized upon the execution of the agreement, when collectability is reasonably assured, or upon receipt of the minimum upfront license fee, and when all other revenue recognition criteria have been met. Certain of the Company’s patent licensing agreements provide for future royalties or future payment obligations triggered upon satisfaction of conditions. Future royalties and future payments are recognized in revenue upon satisfaction of any related conditions, provided that all revenue recognition criteria, as described below, have been met. The Company sells patents from its portfolios from time to time. These sales are part of the Company’s ongoing operations. Consequently, the related proceeds are recorded as revenue. The timing and amount of revenue recognized from IP monetization activities depend on the specific terms of each agreement and the nature of the deliverables and obligations. Fees earned from IP consulting services are generally recognized as the services are performed. For agreements that are deemed to contain multiple elements, consideration is allocated to each element of an agreement that has stand-alone value using the relative fair value method. The Company recognizes revenue when (i) persuasive evidence of an arrangement exists, (ii) all material obligations have been substantially performed pursuant to agreement terms, services have been rendered to the customer or delivery has occurred, (iii) amounts are fixed or determinable, and (iv) collectability is reasonably assured. As a result of the contractual terms of our patent monetization agreements and the unpredictable nature, form and frequency of monetizing transactions, our revenue may fluctuate substantially from period to period. Research and Development— The Company incurs costs associated with research and development activities and expenses the costs in the period incurred. Research and development expenses during the period were not material for separate disclosure and are included in general and administrative expenses. Stock-Based Compensation— The Company records stock-based compensation on stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock awards issued to employees, directors, consultants and/or advisors based on the estimated fair value on the date of grant and recognizes compensation cost over the requisite service period for awards expected to vest. The fair value of stock options and stock appreciation rights is estimated on the date of grant using the Black-Scholes option pricing model (“Black-Scholes Model”) based on the single option award approach. The fair value of restricted stock awards and restricted stock units is determined based on the number of shares granted and either the quoted market price of the Company’s Class A common stock on the date of grant for time-based and performance-based awards, or the fair value on the date of grant using the Monte Carlo Simulation model (“Monte Carlo Simulation”) for market-based awards. The fair value of stock options, restricted stock awards and restricted stock units with service conditions are amortized to expense on a straight-line basis over the requisite service periods of the awards, which is generally the vesting period. The fair value of stock options, stock appreciation rights, restricted stock awards and restricted stock units with performance conditions deemed probable of being achieved and cliff vesting is amortized to expense over the requisite service period using the straight-line method of expense recognition. The fair value of restricted stock awards and restricted stock units with performance and market conditions are amortized to expense over the requisite service period using the straight-line method of expense recognition. The fair value of stock-based payment awards as determined by the Black-Scholes Model and the Monte Carlo Simulation are affected by the Company’s stock price as well as other assumptions. These assumptions include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors. On January 1, 2017, the Company elected to change its accounting policy for calculating stock-based compensation based on forfeiture estimates to one that recognizes forfeitures when they occur (see “New Accounting Pronouncements” below). Previously, forfeitures were estimated at the date of grant and revised, if necessary, in subsequent periods if actual forfeitures differed from those estimates. In certain situations, the Company accounts for changes in the terms or conditions of a stock-based payment award as an exchange of the original award for a new award pursuant to the rules governing modification accounting. Compensation expense for modified stock-based payment awards is generally equal to the fair value of the original award plus the incremental cost conveyed as a result of the modification expensed over the remaining life of the award. Income Taxes— The Company accounts for income taxes using the asset and liability method under which deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded when it is more likely than not that the assets will not be realized. The Company records an unrecognized tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by the tax authorities. The Company’s policy is to recognize interest and/or penalties related to unrecognized tax benefits as income tax expense. Contingencies— Outcomes of legal proceedings and claims brought by and against the Company are subject to significant uncertainty. The Company accrues an estimated loss from a loss contingency, such as a legal claim, by a charge to income if it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. The Company discloses a contingency if there is at least a reasonable possibility that a loss has been incurred. In determining whether a contingent loss should be accrued or disclosed, the Company evaluates, among other factors, the degree of probability of an unfavorable outcome and the ability to make a reasonable estimate of the amount of loss. Changes in these factors could materially impact the Company’s financial position, results of operations or cash flows. For contingencies that might result in a gain, the Company does not record the gain until realized. Income (Loss) Per Share —Basic income (loss) per share is calculated based on the weighted average number of Class A common stock and Class B common stock (the “Common Shares”) outstanding during the period. Diluted income (loss) per share is calculated by dividing the income (loss) allocable to common shareholders by the weighted average Common Shares outstanding plus potential dilutive Common Shares. Prior to the satisfaction of vesting conditions, unvested restricted stock awards are considered contingently issuable and are excluded from weighted average Common Shares outstanding used for computation of basic income (loss) per share. Potential dilutive Common Shares consist of the incremental Class A common stock issuable upon the exercise of outstanding stock options (both vested and non-vested) and unvested restricted stock awards and units, calculated using the treasury stock method. The calculation of dilutive loss per share for the year ended December 31, 2015 excludes all potential dilutive Common Shares as their inclusion would have been antidilutive. The following table sets forth the computation of basic and diluted income (loss) per share (in thousands, except share and per share data): Year ended December 31, 2017 2016 2015 Net income (loss) attributable to Pendrell $ 19,060 $ 17,763 $ (109,680 ) Weighted average common shares outstanding 250,428 268,276 267,136 Less: weighted average unvested restricted stock awards (562 ) (687 ) (1,429 ) Shares used for computation of basic income (loss) per share 249,866 267,589 265,707 Add back: weighted average unvested restricted stock awards and units 6,948 9,329 — Shares used for computation of diluted income (loss) per share (1) 256,814 276,918 265,707 Basic income (loss) per share attributable to Pendrell $ 76.28 $ 66.38 $ (412.79 ) Diluted income (loss) per share attributable to Pendrell $ 74.22 $ 64.15 $ (412.79 ) (1) Stock options, restricted stock awards and units totaling 12,500, 13,053 and 27,847 for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from the calculation of diluted income (loss) per share as their inclusion was anti-dilutive. New Accounting Pronouncements — In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) No. 2016-02, Leases (Topic 842) , which requires companies that are lessees to recognize a right-of-use asset and lease liability for most leases that do not meet the definition of a short-term lease. For income statement purposes, leases will continue to be classified as either operating or financing. Classification will be based on criteria that are similar to those applied in current lease accounting. Compliance with this ASU is required for annual periods beginning after December 15, 2018, and interim periods therein. Early adoption is permitted. As the Company’s future minimum lease commitments as of December 31, 2017 are approximately $0.6 million, the Company believes the future adoption of this ASU will not have a material impact on its financial position, results of operations or cash flows. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting Throughout the year ended December 31, 2016, the FASB issued a number of ASUs which provide further clarification to ASU No. 2014-09, Revenue (Topic 606): Revenue from Contracts with Customers In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718)-Scope of Modification Accounting, required f r o d g n e 5 20

Provitro

Provitro	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Provitro	3. Provitro In February 2013, the Company acquired a 68.75% interest in Provitro, the developer of the Provitro™ proprietary micro-propagation technology designed to facilitate the production on a commercial scale of certain plants, particularly timber bamboo. In February 2015, the Company acquired the minority partner’s interest in Provitro for nominal consideration resulting in 100% ownership of Provitro. From acquisition through the year ended December 31, 2014, the Company attempted to develop a strategy to commercialize Provitro’s proprietary micro-propagation technology (designed to facilitate the production on a commercial scale of certain plants, particularly timber bamboo), but did not generate revenue from the technology. In January 2015, the Company discontinued its efforts to commercialize the Provitro™ technology and in September 2015, the Company sold Provitro’s facility and related tangible assets for $2.0 million. The purchase price was paid in installments of which $0.1 million was paid immediately, $0.4 million was received in January 2016, $0.9 million was received in August 2016 and $0.6 million was received in January 2017.

Accounts Receivable (Current an

Accounts Receivable (Current and Non-current)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable (Current and Non-current)	4. Accounts Receivable (Current and Non-current) A significant portion of the Company’s current accounts receivable balance is due from Toshiba Memory Corporation (“TMC”), which prior to 2017 was a division of Toshiba Corporation (“Toshiba”). Based on the Company’s assessment of various reports, including Toshiba’s unaudited financial results, as well as the ongoing activities of TMC, the Company believes that no allowance for doubtful accounts is required for its receivable from TMC. The Company will continue to evaluate its position as new information becomes available. The Company expects to receive the $1.3 million of non-current accounts receivable at December 31, 2017, in 2019.

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	5. Intangible Assets and Goodwill 2015 Impairment of Intangible Assets and Goodwill In November 2015, as a result of non-infringement verdicts in the Company’s lawsuits against various manufacturers of mobile communication and computing devices (see Note 7 – “Commitments and Contingencies”), the Company revised its projected cash flows for its intangible assets, triggering an impairment analysis of its intangible assets and goodwill. The Company records an impairment charge on its intangible assets if it determines that their carrying value may not be recoverable. The carrying value is not recoverable if it exceeds the undiscounted cash flows resulting from the use of the asset and its eventual disposition. When the Company determines that the carrying value of its intangible assets may not be recoverable, the Company measures the potential impairment based on a projected discounted cash flow method using a discount rate determined by its management to be commensurate with the risk inherent in its current business model. An impairment loss is recognized only if the carrying amount of the intangible assets exceeds its estimated fair value. An impairment charge is recorded to reduce the pre-impairment carrying amount of the intangible assets to their estimated fair value. Determining the fair value is highly judgmental in nature and requires the use of significant estimates and assumptions considered to be Level 3 fair value inputs, including anticipated future revenue opportunities, operating margins, and discount rates, among others. The estimated fair value of the intangible assets was determined based on the income approach, as it was deemed to be most indicative of the Company's fair value in an orderly transaction between market participants. Under the income approach the Company determined fair value based on estimated future cash flows resulting from licensing its intangible assets. The estimated cash flows were discounted by an estimated weighted-average cost of capital which reflects the overall level of inherent risk of the Company and the rate of return an outside investor would expect to earn. Upon completion of the analysis, the Company concluded that the estimated fair value of its intangible assets was less than their carrying amount and recorded an impairment charge of $82.3 million, which is included in "impairment of intangible assets and goodwill" in the accompanying consolidated statements of operations. The Company then evaluated the carrying value of its goodwill by estimating the fair value of the reporting unit through the use of discounted cash flow models, which required management to make significant judgments as to the estimated future cash flows resulting from licensing its intangible assets. Upon completion of the analysis, the Company concluded that the estimated fair value of its reporting unit was less than its carrying amount and recorded an additional $21.2 million impairment charge related to goodwill in the fourth quarter of 2015. As a result of the impairment in 2015, the Company no longer maintains balances for goodwill or indefinite-lived intangible assets in its financial statements. Intangible Assets The following table presents details of the Company’s intangible assets and related amortization (in thousands): December 31, 2017 December 31, 2016 Patent cost $ 58,553 $ 65,796 Patent accumulated amortization (56,224 ) (61,080 ) Intangible assets, net $ 2,329 $ 4,716 Amortization expense related to purchased intangible assets, reported as amortization of intangible assets in the consolidated statements of operations, for the years ended December 31, 2017, 2016 and 2015 were as follows (in thousands): Year ended December 31, 2017 2016 2015 Amortization of intangible assets $ 2,345 $ 9,498 $ 13,939 The intangible assets at December 31, 2017 will be fully amortized as of December 31, 2018. The Company has used, and may continue to use, different structures and forms of consideration for its acquisitions of intangible assets. Acquisitions may be consummated through the use of cash, equity, seller financing, third party debt, earn-out obligations, revenue sharing, profit sharing, or some combination of these types of consideration. Consequently, the acquisition values reflected in the Company’s investing activities may represent lower amounts than would be reflected, for example, in a situation where cash alone was utilized to complete the acquisition. During the year ended December 31, 2015, the Company enhanced its existing memory and storage technologies patent portfolio for an additional $2.0 million. No patents were purchased during the years ended December 31, 2017 and 2016. During the years ended December 31, 2017 and 2015, the Company sold certain patents in several transactions and has included the gross proceeds in revenue. No patents were sold during the year ended December 31, 2016. Cost associated with the patents sold, including any remaining net book value, are included in cost of revenues in the Company’s consolidated statements of operations. The patents sold in 2017 had previously been fully impaired, therefore, there was no related book value to charge to cost of revenues. Certain of the patents sold, as well as certain of those licensed, were subject to an obligation to pay a substantial portion of the net proceeds to a third party. These costs are also included in cost of revenues. In future periods, these third party payments as a percentage of revenues may vary significantly based on the structure utilized for any given acquisition. Costs associated with patents sold during the years ended December 31, 2017, 2016 and 2015 were as follows (in thousands): Year ended December 31, 2017 2016 2015 Cost of patents sold $ — $ — $ 138 The Company periodically abandons patents that are not part of existing licensing programs or for which the Company has determined that it would no longer allocate resources to their maintenance and enforcement. Costs associated with the abandonment of patents, including any remaining net book value, are included in “patent administration and related costs” in the Company’s consolidated statements of operations and were as follows for the years ended December 31, 2017, 2016 and 2015 (in thousands): Year ended December 31, 2017 2016 2015 Cost associated with the abandonment and/or disposition of patents $ 41 $ 163 $ 958

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses The following table summarizes accrued expenses (in thousands): December 31, 2017 December 31, 2016 Accrued payroll and related expenses $ 1,915 $ 1,134 Accrued legal, professional and other expenses 782 538 Accrued revenue share obligations 6,100 4,606 $ 8,797 $ 6,278

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Lease and Commitments— The Company has operating lease agreements for its main office in Kirkland, Washington, and its office in Finland. The Company terminated its lease for office space in Plano, Texas effective June 30, 2016. Total rental expense included in general and administrative expenses in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Rent expense $ 282 $ 245 $ 793 As of December 31, 2017, future minimum payments under the Company’s lease agreements were as follows (in thousands): Operating leases 2018 $ 348 2019 205 Total minimum payments $ 553 Litigation— In the opinion of management, except for those matters described below and elsewhere in this report, to the extent so described, litigation, contingent liabilities and claims against the Company in the normal course of business are not expected to involve any judgments or settlements that would be material to the Company’s financial condition, results of operations or cash flows. ContentGuard Enforcement Actions —In July 2017, the Federal District Court rejected our appeal of unfavorable jury awards in two infringement lawsuits that ContentGuard filed in the Eastern District of Texas against various manufacturers of mobile communication and computing devices. Early in 2018, ContentGuard licensed its patents to ZTE Corporation and dismissed proceedings that ContentGuard’s German subsidiary had filed against ZTE in Germany. These events brought to a close ContentGuard’s various litigation initiatives against manufacturers of mobile communication and computing devices. MTL Enforcement Actions Against SanDisk— In December 2016, the Company’s wholly-owned subsidiary, Memory Technologies LLC (“MTL”) filed patent infringement claims against SanDisk Corporation and certain affiliated companies, including Western Digital Corporation (collectively, “SanDisk”) at the International Trade Commission and in the Federal District Court for the Central District of California, through which MTL sought monetary damages for SanDisk’s alleged infringement of MTL’s patents. In June 2017, MTL licensed its patents to SanDisk and dismissed its actions against SanDisk. MTL On January 31, 2018, MTL filed patent infringement claims against Kingston Technology Corporation and certain affiliated companies (collectively, “Kingston”) in the Federal District Court for the Central District of California (the “Kingston Litigation”), through which MTL seeks monetary damages for Kingston’s alleged infringement of MTL’s patents. The Company is unable to anticipate the timing or outcome of the Kingston Litigation.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shareholders' Equity	8. Shareholders’ Equity Common Stock— The Company’s Articles of Incorporation authorizes two classes of common stock, Class A and Class B. The rights of the holders of shares of Class A common stock and Class B common stock are identical, except with respect to voting and conversion. Holders of shares of Class A common stock are entitled to one vote per share. Holders of shares of Class B common stock are entitled to ten votes per share. The Class B common stock is convertible at any time at the option of its holder into shares of Class A common stock. Each share of Class B common stock is convertible into one share of Class A common stock. Additionally, subject to certain exceptions, shares of Class B common stock will automatically convert into shares of Class A common stock if the shares of Class B common stock are sold or transferred. Class A common stock is not convertible. Eagle River Satellite Holdings, LLC, the Company’s controlling shareholder, together with its affiliates Eagle River Investments, LLC, Eagle River, Inc. and Eagle River Partners, LLC held an economic interest of approximately 37.4% and a voting interest of approximately 67.6% in the Company as of December 31, 2017. On March 9, 2017, the Company redeemed 24,328 shares of the Company’s Class A Stock from Highland Crusader Offshore Partners, L.P. in a private transaction at a price of $655 per share . In the fourth quarter of 2017, the Company redeemed an additional 6,150 shares from various investors in private transactions and as fractionalized shares at an average price of $606 per share. Dividend— On November 30, 2017, the Board declared a dividend of $12.32 per share, payable on shares outstanding after the 2017 Reverse Split. The dividend was paid on December 27, 2017 to shareholders of record on December 15, 2017. The Company elected to pay the dividend to shareholders, rather than incur personal holding company tax. See Note 11 – “Income Taxes” for further details. Prior to 2017, the Company had never paid cash dividends on shares of its Class A or Class B common stock. Stock Incentive Plan— On November 14, 2012, the Company’s shareholders approved the Pendrell Corporation 2012 Equity Incentive Plan (the “2012 Plan”). Effective upon the approval of the 2012 Plan, the Company’s 2000 Stock Incentive Plan, as amended and restated (the “2000 Plan”) was terminated. No additional awards will be granted under the 2000 Plan. The purpose of the 2012 Plan is to assist the Company in securing and retaining the services of skilled employees, directors, consultants and/or advisors of the Company and to provide incentives for such individuals to exert maximum efforts toward the Company’s success. The 2012 Plan allows for the grant of stock options, stock appreciation rights, performance stock awards, performance cash awards, restricted stock awards, restricted stock unit awards and other stock awards (collectively, “Awards”) to employees, directors, consultants and/or advisors who provide services to the Company or its subsidiaries. Under the 2012 Plan, the aggregate number of shares of Class A common stock that may be issued pursuant to Awards from and after the effective date of the 2012 Plan will not exceed, in the aggregate, the sum of 37,952 shares, plus any shares subject to outstanding stock awards granted under the 2000 Plan that (i) expire or terminate for any reason prior to exercise or settlement; (ii) are forfeited, canceled or otherwise returned due to the failure to meet a condition required to vest such shares; or (iii) are reacquired, withheld or not issued to satisfy a tax withholding obligation in connection with an award. As of December 31, 2017, 24,743 shares were reserved and remain available for grant under the 2012 Plan. Stock-Based Compensation— The Company records stock-based compensation based on the estimated fair value on the date of grant and recognizes compensation cost over the requisite service period for awards expected to vest. On January 1, 2017, the Company elected to change its accounting policy for calculating stock-based compensation based on forfeiture estimates to one that recognizes forfeitures when they occur. ASU 2016-09 permits this one-time policy change, but requires the change to be adopted utilizing the modified retrospective approach, with a cumulative effect adjustment recorded to retained earnings. The adoption of this change in accounting for forfeitures on January 1, 2017 resulted in an adjustment to retained earnings and additional paid in capital of approximately $0.2 million. The Company’s estimated forfeiture rate was 5% for the years ended December 31, 2016 and 2015. Stock-based compensation expense included in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Stock options $ 884 $ 1,193 $ 2,236 Restricted stock awards (1) 2,538 2,231 2,271 Total stock-based compensation expense $ 3,422 $ 3,424 $ 4,507 ( 1 ) Stock-based compensation expense for the year ended December 31, 2015 includes $0.2 million of expense related to 250 Class A common stock restricted stock awards that were required to be treated as a liability. The Company settled the related liability with a $2.5 million payment in April 2015 and no further expense has been incurred. At December 31, 2017, the balance of stock-based compensation cost to be expensed in future years related to unvested stock-based awards is $2.1 million, all of which will be expensed in 2018. The $2.1 million of future expense does not include expense related to 500 performance-based stock options and 1,000 performance-based restricted stock awards granted in 2015, as these awards vest upon the achievement of certain performance milestones for which the related performance targets have yet to be established. The fair value of these awards will not be known until the date the performance targets are established at which point expensing will commence. Additionally, the $2.1 million of future expense does not include additional stock-based compensation resulting from the modification of options and restricted stock outstanding at December 31, 2017 during the first quarter of 2018. See Note 15 – “Subsequent Events.” Stock Options and Stock Appreciation Rights— The Company has granted stock options and stock appreciation rights to employees, directors, consultants and advisors in connection with their service to the Company. Stock options to purchase the Company’s Class A common stock are granted at the fair market value of the stock on the date of grant. The Company has both service-based stock options and performance-based stock options. The majority of service-based stock options granted to employees become exercisable over a four year period, while stock options granted to non-employee directors generally vest over one year. Performance-based stock options become exercisable if the Company achieves specified performance goals during the performance period and the grantee remains employed during the subsequent vesting period. Stock options generally expire 10 years after the date of grant or up to three months after termination of employment, whichever occurs earlier. There are no stock appreciation rights currently outstanding. The weighted average fair value of stock options granted during the years ended December 31, 2017, 2016 and 2015 was estimated using the Black-Scholes Model with the following assumptions: Year ended December 31, 2017 2016 2015 Weighted average expected volatility 49 % 53 % 48 % Weighted average risk-free interest rate 2.0 % 1.2 % 1.9 % Expected dividend yield 0 % 0 % 0 % Weighted average expected term in years 5.5 5.5 6.0 Weighted average estimated fair value per option granted $ 319.70 $ 332.00 $ 470.00 The assumptions used to calculate the fair value are evaluated and revised, as necessary, to reflect market conditions and the Company’s experience. The Company’s expected stock price volatility rate is based on a peer group, which the Company believes is a reasonable representation of the Company’s business direction and expected future volatility as an IP investment and asset management business. The risk-free interest rate is based upon U.S. Treasury bond interest rates appropriate for the term of the Company’s employee stock options. The expected dividend yield is based on the Company’s history and expectation of dividend payments. The expected term has been estimated using the simplified method which permit entities, under certain circumstances, to continue to use the simplified method in developing estimates of the expected term of “plain-vanilla” share options. The Company’s stock option activity for the year ended December 31, 2017 is summarized as follows: Number of options Weighted average exercise price Weighted average remaining life (in years) Outstanding at December 31, 2016 13,045 $ 1,569.84 Granted (1) 240 687.00 Forfeited (785 ) 2574.43 Outstanding at December 31, 2017 (2) 12,500 $ 1,489.80 6.04 Exercisable at December 31, 2017 (2) 9,552 $ 1,547.53 5.60 Vested and expected to vest at December 31, 2017 (2) 12,500 $ 1,489.80 6.04 (1) All options granted were to members of the Company’s board of directors. (2) Aggregate intrinsic value represents the amount by which the market value of the underlying stock exceeded the exercise price of outstanding options, before applicable income taxes and represents the amount optionees would have realized if all in-the-money options had been exercised on December 31, 2017. As of December 31, 2017, the aggregate intrinsic values of stock options outstanding, exercisable, and vested and expected to vest were all zero as the closing stock price of the Company’s stock was lower than the exercise prices of its outstanding options. The total fair value of options which vested during the years ended December 31, 2017, 2016 and 2015 was approximately $1.0 million, $2.0 million and $2.5 million, respectively. The following table summarizes significant ranges of outstanding and exercisable stock options as of December 31, 2017: Outstanding stock options Exercisable stock options Range of exercise prices Number of options Weighted average exercise price Weighted average remaining life (in years) Number of options Weighted average exercise price $ 687—$1,255 2,570 $ 1,039 5.57 2,330 $ 1,076 $1,256—$1,325 1,925 1,304 7.21 1,522 1,302 $1,326—$1,405 4,000 1,340 7.46 2,000 1,340 $1,406—$1,845 1,872 1,562 4.96 1,567 1,568 $1,846—$2,780 2,133 2,418 3.87 2,133 2,418 12,500 $ 1,490 6.04 9,552 $ 1,548 See Note 15 – “Subsequent Events” for discussion regarding 2018 modification, including cancellation, of options outstanding at December 31, 2017. Restricted Stock Awards— The Company has granted restricted stock awards to employees, directors and consultants in connection with their service to the Company. The Company’s stock grants can be categorized as either service-based awards, performance-based awards, and/or market-based awards. The Company’s restricted stock award activity for the year ended December 31, 2017 is summarized as follows: Number of restricted stock awards Weighted average grant date fair value Unvested—December 31, 2016 8,907 $ 822.67 Granted (1) 625 681.67 Vested (2,719 ) 817.39 Forfeited (162 ) 522.93 Unvested—December 31, 2017 (2) 6,651 $ 904.00 (1) Represents shares issued to the Company’s Board of Directors as compensation for service. These awards have a grant date fair value of $0.4 million and vest upon issuance. ( 2 ) 2,089 of the awards outstanding at December 31, 2017 will either vest or expire in 2018, with the balance either vesting or expiring in 2019. During the year ended December 31, 2017, 2,094 restricted stock awards vested as a result of the Company’s employees achieving service and performance targets. Certain holders of the vested RSAs and RSUs exercised their right to have their awards net-share settled to cover statutory employee taxes related to the vesting of the RSAs and RSUs. The settlement of these awards resulted in the Company repurchasing and/or cancelling 24 shares for approximately $17,000. See Note 15 – “Subsequent Events” for discussion regarding the 2018 modification, including cancellation, of restricted stock outstanding at December 31, 2017.

Contract Termination Costs

Contract Termination Costs	12 Months Ended
	Dec. 31, 2017
Contract Termination Costs [Abstract]
Contract Termination Costs	9. Contract Termination Costs Pursuant to the 2013 agreement under which the Company acquired the bulk of its memory and storage technologies portfolio, the Company shared a significant portion of the revenue generated from memory patents with the seller. On February 23, 2017, the seller agreed to relinquish its future revenue share in exchange for an up-front payment and future installment payments.

Gain on Contingencies

Gain on Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Gain on Contingencies	10. Gain on Contingencies During 2012, as part of the Company’s exit from the satellite business, the Company sold its MEO Assets that had been in storage for nominal consideration. Under the sales agreement, the Company was entitled to a substantial portion of any proceeds that the buyer generated from the resale of the MEO Assets. In January 2015, the buyer resold the MEO Assets and the Company received two of three scheduled payments for these assets in 2015, resulting in the recognition of $3.9 million gain on contingency in the year ended December 31, 2015. The Company received the final scheduled payment in April 2016, resulting in the recognition of a $2.0 million gain on contingency in the year ended December 31, 2016. In March 2012, the Company asserted claims in arbitration in London against the J&J Group to recover costs that the J&J Group was required to reimburse the Company pursuant to a MEO satellite asset purchase agreement that was signed in April 2011. In November 2015, the Company entered into a settlement agreement with the J&J Group whereby it received approximately $1.6 million, net of collection costs, in full and final settlement of all claims against the J&J Group which is included in gain on contingencies in the statements of operations for the year ended December 31, 2015. Additionally, the Company recorded a gain of $0.5 million during 2015 as a result of the release of a tax indemnification liability associated with the acquisition of Ovidian in June 2011.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company’s income tax benefit (expense) for the years ended December 31, 2017, 2016 and 2015 consists of the following (in thousands): Year ended December 31, 2017 2016 2015 United States—current $ 2,182 $ — $ — United States—deferred — — 1,497 Foreign—current (72 ) — (4,128 ) Income tax benefit (expense) $ 2,110 $ — $ (2,631 ) For the year ended December 31, 2017, the Company recorded an income tax benefit of $2.1 million primarily related to a state income tax refund of prior year taxes approved by tax authorities in late 2017. For the year ended December 31, 2016, the Company did not record a provision for U.S. federal income tax due to available tax loss carryforwards. During the year ended December 31, 2015, as a result of the impairment of certain indefinite-lived intangible assets, the deferred tax liability associated with these intangible assets decreased, resulting in a federal tax benefit of $1.5 million. For the years ended December 31, 2017 and 2015, the Company recorded tax provisions of $0.1 million and $4.1 million, respectively, related to foreign taxes withheld on revenue generated from license agreements executed with third party licensees domiciled in foreign jurisdictions. The Company had no foreign taxes withheld during the year ended December 31, 2016. In general, foreign taxes withheld may be claimed as a deduction on future U.S. corporate income tax returns, or as a credit against future U.S. federal income tax liabilities, subject to certain limitations. However, due to uncertainty regarding the Company’s ability to utilize the deduction or credit resulting from the foreign withholding, the Company established a full valuation allowance against the related deferred tax asset. The Company’s accounting for the various elements of the Tax Cuts and Jobs Act (“TCJA”), enacted on December 22, 2017, is complete and the impact is reflected in the 2017 financial statements, including the reduction in the maximum U.S. federal corporate tax rate from 35% to 21% beginning in 2018. As a result of the TCJA, the Company recorded a $323.2 million reduction in its net deferred tax assets to reflect the new statutory tax rate. This adjustment to deferred tax assets was fully offset by a corresponding decrease in the Company’s valuation allowance, resulting in no impact to the Company’s effective tax rate. A reconciliation of the 2017, 2016 and 2015 federal statutory income tax rate of 34% to the Company’s effective income tax rate is as follows: Year ended December 31, 2017 2016 2015 Statutory tax rate 34.00 % 34.00 % 34.00 % Change in valuation allowance (1,862.16 ) (59.30 ) (22.59 ) Impact of change in tax law 1,821.35 — — State income taxes (8.01 ) — — Foreign withholding taxes 0.26 — (2.37 ) Goodwill impairment — — (6.07 ) Stock-based compensation 1.42 10.24 (3.23 ) Loss on sale of subsidiary — 13.70 — Other 1.24 1.36 (2.03 ) Effective tax rate (11.90 )% 0 % (2.29 )% The significant components of the Company’s net deferred tax assets are as follows (in thousands): December 31, 2017 December 31, 2016 Net deferred tax assets: Net operating losses $ 624,984 $ 941,163 Basis difference in Liquidating Trust 10,380 16,955 Accrued expenses and other 5,083 12,336 Total deferred tax assets 640,447 970,454 Valuation allowance (640,447 ) (970,454 ) Net deferred tax assets $ — $ — As of December 31, 2017, the Company had federal tax net operating loss carryforwards in the United States (“NOLs”) of approximately $2.5 billion. A significant portion of the NOLs were generated when the Company disposed of its satellite business and transferred the MEO-related international subsidiaries to a liquidating trust. In 2017, the Company adopted ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The Company believes the NOLs can be carried forward to offset certain future taxable income that may be generated during the carryforward period, which begins to expire in 2025 with a significant portion expiring in 2032. The use of the NOLs will be significantly limited if the Company undergoes a Tax Ownership Change under Section 382 of the Internal Revenue Code (“Tax Ownership Change”). Broadly, the Company will have a Tax Ownership Change if, over a three-year testing period, the portion of all stock of the Company, by value, owned by one or more 5% shareholder increases by more than 50 percentage points. For purposes of this test, shareholders that own less than 5% of the stock of the Company are aggregated into one or more separate “public groups”, each of which is treated as a 5% shareholder. In general, shares traded within a public group are not included in the Tax Ownership Change test. As discussed below, the Board of Directors adopted a Tax Benefits Preservation Plan designed to preserve shareholder value and the value of certain tax assets primarily associated with NOLs. As of December 31, 2017, the Company also had tax loss carryforwards in the state of California of approximately $1.3 billion, which will begin to expire in 2028. A significant portion of the California loss carryforward was generated when the Company disposed of its satellite business and will expire in 2032. The impacts of a Tax Ownership Change, discussed above, apply to the California tax losses as well. For all years presented, the Company has considered all available evidence, including the history of tax losses and the uncertainty around future taxable income. Based on the weight of the evidence available at December 31, 2017, a valuation allowance has been recorded to reduce the value of the Company’s deferred tax assets deferred tax assets At the beginning of the year ended December 31, 2017, the Company had unrecognized tax benefits of $15.3 million related to income tax refund claims filed in various jurisdictions. In late 2017, the Company settled a claim for the partial refund of state income taxes previously paid, resulting in a refund of $2.2 million, which is expected to be received in early 2018, and a reduction to the Company’s unrecognized tax benefits of $3.0 million. Due to the uncertain nature of the Company’s remaining refund claims, the remaining uncertain tax positions have not yet been recorded as an income tax benefit. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): December 31, 2017 2016 2015 Beginning of period $ 15,323 $ 15,594 $ 5,132 Additions for tax positions taken during the current period — — 10,462 Reductions periods (2,950 ) — — Settlements with tax authorities (2,182 ) — — Exchange rate fluctuations 1,352 (271 ) — End of period $ 11,543 $ 15,323 $ 15,594 All of the unrecognized tax benefits at December 31, 2017, if fully recognized, would affect the Company’s effective tax rate. The Company estimates that a reduction in its unrecognized tax benefits of approximately $11.5 million may occur within the next twelve months upon resolution of determinations by taxing authorities. The Company and its subsidiaries file U.S. federal income tax returns and tax returns in various state and foreign jurisdictions. The Company is open to examination for the years ended 2005 and forward with respect to NOLs generated and carried forward from those years. The Company is open to examination by foreign jurisdictions for tax years 2013 forward. Certain Taxes Payable Irrespective of NOLs —Under the Internal Revenue Code and related Treasury Regulations, the Company may “carry forward” its NOLs in certain circumstances to offset current and future income and thus reduce its federal income tax liability, subject to certain restrictions. To the extent that the NOLs do not otherwise become limited, the Company believes that it will be able to carry forward a significant amount of NOLs. However, these NOLs will not impact all taxes to which the Company may be subject. For instance, state or foreign income taxes and/or revenue based taxes may be payable if the Company’s income or revenue is attributed to jurisdictions that impose such taxes, and the NOLs will not offset any federal personal holding company tax liability that Pendrell or one or more of its corporate subsidiaries may incur. This is not an exhaustive list, but merely illustrative of the types of taxes to which the Company’s NOLs are not applicable. Personal Holding Company Determination —The Internal Revenue Code imposes an additional tax on the undistributed income of a Personal Holding Company (“PHC”). In general, a corporation will be classified as a PHC if 50% or more of its outstanding shares, measured by value, are owned directly or indirectly by five or fewer individual shareholders at any time during the second half of the year (“Concentrated Ownership”) and at least 60% of its adjusted ordinary gross income is Personal Holding Company Income (“PHCI”). Broadly, PHCI includes items such as dividends, interest, rents and royalties, among others. For a corporate subsidiary, Concentrated Ownership is determined by reference to ownership of the parent corporation, and the subsidiary’s income is subject to additional tests to determine whether its income renders the subsidiary a PHC. If a corporation is a PHC, generates positive net PHCI and does not distribute to its shareholders a proportionate dividend in the full amount of the net PHCI, then the undistributed net PHCI is taxed (at 20% under current law). Due to the significant number of shares held by the Company’s largest shareholders and the type of income that the Company generates, the Company must continually assess share ownership of Pendrell and its consolidated subsidiary ContentGuard to determine whether or not there is Concentrated Ownership of either corporation. For 2017, the Company determined that Pendrell, the parent company, met the Concentrated Ownership test, but that ContentGuard has not yet met the Concentrated Ownership test due to the interest held by its minority shareholders. The Company does not expect to have a PHC liability for 2017 because Pendrell did not have undistributed net PHCI as a result of the $3.0 million dividend payment made to shareholders on December 27, 2017. If either Pendrell or ContentGuard is a PHC in a future tax year, generates net PHCI, and does not distribute to its shareholders a proportionate dividend in the full amount of the net PHCI, then the undistributed net PHCI will be taxed. Tax Benefits Preservation Plan— Effective January 29, 2010, the Board of Directors adopted the Tax Benefits Preservation Plan (“Tax Benefits Plan”) to help the Company preserve its ability to utilize fully its NOLs and to help preserve potential future NOLs. As discussed above, if the Company experiences a “Tax Ownership Change,” as defined in Section 382 of the Internal Revenue Code, the Company’s ability to use the NOLs could be significantly limited. The Tax Benefits Plan is intended to act as a deterrent to any person or group acquiring, without the approval of the Company’s Board of Directors, beneficial ownership of 4.9% or more of the Company’s securities, defined to include: (i) shares of its Class A common stock and Class B common stock, (ii) shares of its preferred stock, (iii) warrants, rights, or options to purchase its securities, and (iv) any interest that would be treated as “stock” of the Company for purposes of Section 382 or pursuant to Treasury Regulation § 1.382-2T(f)(18). Holders of 4.9% or more of the Company’s securities outstanding as of the close of business on January 29, 2010 will not trigger the Tax Benefits Plan so long as they do not (i) acquire additional securities constituting one-half of one percent (0.5%) or more of the Company’s securities outstanding as of the date of the Tax Benefits Plan (as adjusted to reflect any stock splits, subdivisions and the like), or (ii) fall under 4.9% ownership of the Company’s securities and then re-acquire securities that increase their ownership to 4.9% or more of the Company’s securities. The Board of Directors may exempt certain persons whose acquisition of securities is determined by the Board of Directors not to jeopardize the Company’s tax benefits or to otherwise be in the best interest of the Company and its shareholders. The Board of Directors may also exempt certain transactions.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Employee Benefits	12. Employee Benefits The Company provides its eligible employees with medical and dental benefits, insurance arrangements to cover death in service, long-term disability and personal accident, as well as a defined contribution retirement plan. Expense related to contributions by the Company under the defined contribution retirement plan included in general and administrative expenses in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Defined contribution expenses $ 65 $ 80 $ 201

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Parties	13. Related Parties The Company considers its related parties to be its principal shareholder and its affiliates. Eagle River Satellite Holdings, LLC (“ERSH”), Eagle River Investments, LLC (“ERI”), Eagle River, Inc. and Eagle River Partners, LLC (“ERP”)— ERSH is the Company’s controlling shareholder. ERSH, together with its affiliates ERI, Eagle River, Inc. and ERP (collectively, “Eagle River”) holds an economic interest of approximately 37.4% of the Company’s outstanding common stock and a voting interest of approximately 67.6% in the Company as of December 31, 2017. Craig O. McCaw, our Executive Chairman, is the sole manager and beneficial member of ERI, which is the sole member of ERSH. Mr. McCaw is the sole shareholder of Eagle River, Inc. and the beneficial member of ERP. Mr. McCaw disclaims beneficial ownership of the securities owned by ERSH, ERI and ERP, except to the extent of any pecuniary interest.

Quarterly Financial Data

Quarterly Financial Data	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	14. Quarterly Financial Data (Unaudited) The following table contains selected unaudited statement of operations information for each quarter of the years ended December 31, 2017 and 2016. The quarterly financial data reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. During the quarter ended December 31, 2017, the Company reversed its prior tax accrual of $0.6 million related to PHC tax as it chose, instead, to pay a $3.0 million dividend. See Note 11 – “Income Taxes” for further details. Additionally, in the same quarter, the Company recognized a $2.1 million tax benefit associated with the recognition of previously recorded uncertain tax positions. There were no changes in accounting estimates that materially affected the fourth quarter of the year ended December 31, 2016. Unaudited quarterly results were as follows (in thousands, except per share data): Three months ended March 31, June 30, September 30, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 Revenue $ — $ 13,500 $ 35,122 $ 45,003 $ 5,443 $ — $ 2,209 $ 515 Operating income (loss) (8,064 ) 4,928 24,462 21,103 1,918 (5,501 ) (2,165 ) (5,313 ) Net income (loss) (7,783 ) 7,110 24,203 21,257 2,343 (5,341 ) 1,093 (5,077 ) Net income (loss) attributable to Pendrell (7,759 ) 6,565 24,228 21,420 1,713 (5,254 ) 878 (4,968 ) Basic income (loss) per share attributable to Pendrell $ (29.33 ) $ 24.58 $ 98.49 $ 80.07 $ 6.96 $ (19.62 ) $ 3.61 $ (18.54 ) Diluted income (loss) per share attributable to Pendrell $ (29.33 ) $ 23.72 $ 95.80 $ 77.33 $ 6.78 $ (19.62 ) $ 3.51 $ (18.54 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events On January 23, 2018, the Board authorized management to make an offer to certain Company employees to exchange their stock options and restricted stock for future cash payments to be paid out as follows: (i) twenty-five percent (25%) on August 15, 2018, so long as the employee continues as an employee of the Company through that date; (ii) twenty-five percent (25%) on August 15, 2019, so long as the employee continues as an employee of the Company through that date; and (iii) the remaining fifty percent (50%) on August 15, 2020, so long as the employee continues as an employee of the Company through that date. The Company intends to make the offer sometime in the first quarter of 2018. If all employees who receive the offer accept: (i) 3,184 options and 86 restricted stock awards outstanding at December 31, 2017 will be canceled; and (ii) the Company estimates that it may incur an additional $0.7 million of stock-based compensation expense in the year ended December 31, 2018, which represents the incremental fair value of the right to receive cash over the estimated fair value of the canceled stock options and restricted stock, as of the acceptance date.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation— The consolidated financial statements of the Company include the assets and liabilities of its wholly-owned subsidiaries and subsidiaries it controls or in which it has a controlling financial interest. Noncontrolling interests on the consolidated balance sheets include third-party investments in entities that the Company consolidates, but does not wholly own. Noncontrolling interests are classified as part of equity and the Company allocates net income (loss), other comprehensive income (loss) and other equity transactions to its noncontrolling interests in accordance with their applicable ownership percentages. All intercompany transactions and balances have been eliminated in consolidation, including a $31.8 million loan from Pendrell to ContentGuard Holdings, Inc. (“ContentGuard”). In June 2017, the Company sold a 9% interest in ContentGuard. ContentGuard now has two minority shareholders, while Pendrell maintains an 81.1% ownership stake. In February 2015, the Company acquired the minority partner’s interest in Provitro Biosciences LLC (“Provitro”) for nominal consideration resulting in 100% ownership of Provitro. All information in these financial statements is in U.S. dollars. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”).
Capital Structure Change	Capital Structure Change— At the Company’s annual meeting of shareholders in June 2017, the Company’s shareholders approved a 1-for-100 reverse stock split of the Company’s Class A Stock and Class B common stock that was implemented on November 30, 2017 (the "2017 Reverse Split"). The 2017 Reverse Split reduced the Company’s number of record shareholders to less than 300, which allowed it to (i) terminate the Company’s Nasdaq listing, effective December 15, 2017, (ii) file to de-register the Company’s Class A Stock under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which was filed on December 26, 2017; and (iii) cease to be a reporting company under the Exchange Act after the Company’s notice of de-registration is effective, which will be no later than March 26, 2018. On September 20, 2017, the Company’s Board of Directors (the “Board”) announced that the Company does not currently plan to publish financial information following the expiration of its reporting obligations under the Exchange Act. As a result, the Company believes this Form 10-K for fiscal year ended December 31, 2017 will be its final financial statement filed with the Securities and Exchange Commission. In September 2016, the Company consummated a 1-for-10 reverse stock split (the “2016 Reverse Split”) to remediate a stock price deficiency as required by Nasdaq’s continued listing requirements. As a result of the 2017 and 2016 Reverse Splits, the share counts and per share data reported in the historical financial statements have been adjusted retrospectively as if the 2017 and 2016 Reverse Splits had been in effect for all periods presented. Additionally, the exercise prices and the number of shares issuable under the Company’s stock-based compensation plans have been adjusted retrospectively to reflect the 2017 and 2016 Reverse Splits.
Segment Information	Segment Information— The Company operates in and reports on one segment (IP management). Operating segments are based upon the Company’s internal organization structure, how its operations are managed, and the criteria used by its Chief Operating Decision Maker. Substantially all of the Company’s revenue is generated by operations located within the United States, and the Company does not have any long-lived assets located in foreign countries.
Use of Estimates	Use of Estimates— The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from these estimates. On an ongoing basis, the Company evaluates its estimates, including among others, those related to the fair value of acquired intangible assets, the useful lives and potential impairment of intangible assets and property and equipment, the value of stock awards for the purpose of determining stock-based compensation expense, accrued liabilities (including bonus accruals), valuation allowances related to the ability to realize deferred tax assets, allowances for doubtful receivables, and certain tax liabilities. Estimates are based on historical experience and other factors, including the current economic environment as deemed appropriate under the circumstances. Estimates and assumptions are adjusted when facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Any changes in estimates used to prepare these financial statements will be reflected in future periods.
Cash and Cash Equivalents	Cash and Cash Equivalents— Cash and cash equivalents are defined as short-term, highly liquid investments with original maturities from the date of purchase of 90 days or less. Cash and cash equivalents are comprised of the following (in thousands): December 31, 2017 2016 Cash $ 15,200 $ 13,485 Money market funds 169,282 161,146 $ 184,482 $ 174,631 The fair value of money market funds at December 31, 2017 and 2016 was classified as Level 1 in the hierarchy established by the Financial Accounting Standards Board (“FASB”) as amounts were based on quoted prices available in active markets for identical investments as of the reporting date.
Accounts Receivable	Accounts Receivable— Accounts receivable consist primarily of amounts billed to customers under licensing arrangements. For the years ended December 31, 201 7, 2016 and 2015, the Company did not incur any losses on its accounts receivable. Based upon historical collections experience and currently available information, the Company has determined that no allowance for doubtful accounts was required at either December 31, 2017 or December 31, 2016. Carrying amounts of such receivables approximate their fair value due to their short-term nature.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets— As of December 31, 201 7 and 2016, prepaid expenses and other current assets consisted primarily of insurance prepayments, prepayments of patent maintenance fees and prepayments of rent for leased facilities.
Property in Service	Property in Service— Property in service consists primarily of computer equipment, software, furniture and fixtures and leasehold improvements. Property in service is recorded at cost, net of accumulated depreciation, and is depreciated using the straight-line method. Computer equipment and furniture and fixtures are depreciated over their estimated useful lives ranging from three to five years. Software is depreciated over the shorter of its contractual license period or three years. Leasehold improvements are amortized over the shorter of their estimated useful lives or the term of the respective lease. Significant additions and improvements to property in service are capitalized. Repair and maintenance costs are expensed as incurred.
Intangible Assets and Goodwill	Intangible Assets and Goodwill— The Company amortizes finite-lived intangible assets, including patents, acquired in purchase transactions over their expected useful lives. The Company assigns goodwill and indefinite-lived intangible assets to its reporting units based on the expected benefit from the synergies arising from each business combination. The Company evaluates finite-lived intangible assets when events or circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. These events or circumstances could include: a significant change in the business climate, legal factors, operating performance indicators, or changes in technology or customer requirements. Recoverability of an asset or asset group is measured by a comparison of the carrying amount to the future undiscounted net cash flows expected to be generated by the asset or asset group over its life. This comparison requires management to make judgments regarding estimated future cash flows. The Company’s ability to realize the estimated future cash flows may be affected by factors such as changes in operating performance, changes in business strategy, invalidation of patents, unfavorable judgments in legal proceedings and changes in economic conditions. If the Company’s estimates of the undiscounted cash flows do not equal or exceed the carrying value of the asset or asset group, an impairment charge equal to the amount by which the recorded value of the asset or asset group exceeds its fair value is recognized. The Company previously evaluated goodwill for impairment on an annual basis during the fourth quarter, or more frequently if circumstances indicated that the carrying value of a Company reporting unit may exceed its fair value. When evaluating goodwill and indefinite-lived intangible assets for impairment, the Company first performed a qualitative assessment to determine if fair value of the reporting unit was more likely than not greater than the carrying amount. If the assessment indicated that it was more likely than not that the fair value of a reporting unit was less than its carrying amount, then the Company further evaluated the estimated fair value of the reporting unit through the use of discounted cash flow models, which required management to make significant judgments as to the estimated future cash flows utilized. The Company’s ability to realize the future cash flows utilized in its fair value calculations could be affected by factors such as changes in its operating performance, changes in its business strategy, invalidation of its patents, unfavorable judgments in legal proceedings and changes in economic conditions. The results of the models were compared to the carrying amount of the reporting unit. If such comparison indicated that the fair value of the reporting unit was lower than the carrying amount, impairment would exist and the impairment charge would be measured by comparing the implied fair value of the reporting unit’s goodwill to its carrying value. During 2015, the Company determined that a portion of its intellectual property assets and the balance of its goodwill were impaired and recognized an impairment charge of $103.5 million for the year ended December 31, 2015. As a result of the impairment in 2015, the Company no longer maintains balances for goodwill or indefinite-lived intangible assets in its financial statements.
Fair Value of Financial Instruments	Fair Value of Financial Instruments— The Company determines the fair value of its financial instruments based on the fair value hierarchy established by the FASB. The three levels of inputs used to measure fair value are as follows: Level 1—Quoted prices in active markets for identical assets and liabilities. Level 2—Quoted prices in active markets for similar assets and liabilities or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. Level 3—Unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets and liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. As of December 31, 2017 and 2016, the Company’s financial instruments included its cash and cash equivalents, accounts receivable, other receivables, accounts payable and certain other assets and liabilities. The Company has determined that the carrying value of its financial instruments, based on the hierarchy established by the FASB, approximates the fair value of the financial instruments as they are equivalent to cash or due to their short-term nature.
Revenue Recognition	Revenue Recognition— The Company derives its operating revenue from IP monetization activities, including patent licensing and patent sales; and, in years prior to 2016, from IP consulting services. Although the Company’s revenue may occur in different forms, it regards its IP monetization activities as integrated and not separate revenue streams. For example, a third party relationship could involve consulting and licensing activities, or the acquisition of a patent portfolio can lead to licensing, consulting and patent sales revenue. The Company’s patent licensing agreements often provide for the payment of contractually determined upfront license fees representing all or a majority of the revenue that will be generated from such agreements for nonexclusive, nontransferable, limited duration licenses. These agreements typically grant (i) a nonexclusive license to make, sell, distribute, and use certain specified products that read on the Company’s patents, (ii) a covenant not to enforce patent rights against the licensee based on such activities, and (iii) the release of the licensee from certain claims. Generally, the agreements provide no further obligation for the Company upon receipt of the minimum upfront license fee. As such, the earnings process is complete and revenue is recognized upon the execution of the agreement, when collectability is reasonably assured, or upon receipt of the minimum upfront license fee, and when all other revenue recognition criteria have been met. Certain of the Company’s patent licensing agreements provide for future royalties or future payment obligations triggered upon satisfaction of conditions. Future royalties and future payments are recognized in revenue upon satisfaction of any related conditions, provided that all revenue recognition criteria, as described below, have been met. The Company sells patents from its portfolios from time to time. These sales are part of the Company’s ongoing operations. Consequently, the related proceeds are recorded as revenue. The timing and amount of revenue recognized from IP monetization activities depend on the specific terms of each agreement and the nature of the deliverables and obligations. Fees earned from IP consulting services are generally recognized as the services are performed. For agreements that are deemed to contain multiple elements, consideration is allocated to each element of an agreement that has stand-alone value using the relative fair value method. The Company recognizes revenue when (i) persuasive evidence of an arrangement exists, (ii) all material obligations have been substantially performed pursuant to agreement terms, services have been rendered to the customer or delivery has occurred, (iii) amounts are fixed or determinable, and (iv) collectability is reasonably assured. As a result of the contractual terms of our patent monetization agreements and the unpredictable nature, form and frequency of monetizing transactions, our revenue may fluctuate substantially from period to period.
Research and Development	Research and Development— The Company incurs costs associated with research and development activities and expenses the costs in the period incurred. Research and development expenses during the period were not material for separate disclosure and are included in general and administrative expenses.
Stock-Based Compensation	Stock-Based Compensation— The Company records stock-based compensation on stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock awards issued to employees, directors, consultants and/or advisors based on the estimated fair value on the date of grant and recognizes compensation cost over the requisite service period for awards expected to vest. The fair value of stock options and stock appreciation rights is estimated on the date of grant using the Black-Scholes option pricing model (“Black-Scholes Model”) based on the single option award approach. The fair value of restricted stock awards and restricted stock units is determined based on the number of shares granted and either the quoted market price of the Company’s Class A common stock on the date of grant for time-based and performance-based awards, or the fair value on the date of grant using the Monte Carlo Simulation model (“Monte Carlo Simulation”) for market-based awards. The fair value of stock options, restricted stock awards and restricted stock units with service conditions are amortized to expense on a straight-line basis over the requisite service periods of the awards, which is generally the vesting period. The fair value of stock options, stock appreciation rights, restricted stock awards and restricted stock units with performance conditions deemed probable of being achieved and cliff vesting is amortized to expense over the requisite service period using the straight-line method of expense recognition. The fair value of restricted stock awards and restricted stock units with performance and market conditions are amortized to expense over the requisite service period using the straight-line method of expense recognition. The fair value of stock-based payment awards as determined by the Black-Scholes Model and the Monte Carlo Simulation are affected by the Company’s stock price as well as other assumptions. These assumptions include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors. On January 1, 2017, the Company elected to change its accounting policy for calculating stock-based compensation based on forfeiture estimates to one that recognizes forfeitures when they occur (see “New Accounting Pronouncements” below). Previously, forfeitures were estimated at the date of grant and revised, if necessary, in subsequent periods if actual forfeitures differed from those estimates. In certain situations, the Company accounts for changes in the terms or conditions of a stock-based payment award as an exchange of the original award for a new award pursuant to the rules governing modification accounting. Compensation expense for modified stock-based payment awards is generally equal to the fair value of the original award plus the incremental cost conveyed as a result of the modification expensed over the remaining life of the award.
Income Taxes	Income Taxes— The Company accounts for income taxes using the asset and liability method under which deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded when it is more likely than not that the assets will not be realized. The Company records an unrecognized tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by the tax authorities. The Company’s policy is to recognize interest and/or penalties related to unrecognized tax benefits as income tax expense.
Contingencies	Contingencies— Outcomes of legal proceedings and claims brought by and against the Company are subject to significant uncertainty. The Company accrues an estimated loss from a loss contingency, such as a legal claim, by a charge to income if it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. The Company discloses a contingency if there is at least a reasonable possibility that a loss has been incurred. In determining whether a contingent loss should be accrued or disclosed, the Company evaluates, among other factors, the degree of probability of an unfavorable outcome and the ability to make a reasonable estimate of the amount of loss. Changes in these factors could materially impact the Company’s financial position, results of operations or cash flows. For contingencies that might result in a gain, the Company does not record the gain until realized.
Income (Loss) Per Share	Income (Loss) Per Share —Basic income (loss) per share is calculated based on the weighted average number of Class A common stock and Class B common stock (the “Common Shares”) outstanding during the period. Diluted income (loss) per share is calculated by dividing the income (loss) allocable to common shareholders by the weighted average Common Shares outstanding plus potential dilutive Common Shares. Prior to the satisfaction of vesting conditions, unvested restricted stock awards are considered contingently issuable and are excluded from weighted average Common Shares outstanding used for computation of basic income (loss) per share. Potential dilutive Common Shares consist of the incremental Class A common stock issuable upon the exercise of outstanding stock options (both vested and non-vested) and unvested restricted stock awards and units, calculated using the treasury stock method. The calculation of dilutive loss per share for the year ended December 31, 2015 excludes all potential dilutive Common Shares as their inclusion would have been antidilutive. The following table sets forth the computation of basic and diluted income (loss) per share (in thousands, except share and per share data): Year ended December 31, 2017 2016 2015 Net income (loss) attributable to Pendrell $ 19,060 $ 17,763 $ (109,680 ) Weighted average common shares outstanding 250,428 268,276 267,136 Less: weighted average unvested restricted stock awards (562 ) (687 ) (1,429 ) Shares used for computation of basic income (loss) per share 249,866 267,589 265,707 Add back: weighted average unvested restricted stock awards and units 6,948 9,329 — Shares used for computation of diluted income (loss) per share (1) 256,814 276,918 265,707 Basic income (loss) per share attributable to Pendrell $ 76.28 $ 66.38 $ (412.79 ) Diluted income (loss) per share attributable to Pendrell $ 74.22 $ 64.15 $ (412.79 ) (1) Stock options, restricted stock awards and units totaling 12,500, 13,053 and 27,847 for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from the calculation of diluted income (loss) per share as their inclusion was anti-dilutive.
New Accounting Pronouncements	New Accounting Pronouncements — In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) No. 2016-02, Leases (Topic 842) , which requires companies that are lessees to recognize a right-of-use asset and lease liability for most leases that do not meet the definition of a short-term lease. For income statement purposes, leases will continue to be classified as either operating or financing. Classification will be based on criteria that are similar to those applied in current lease accounting. Compliance with this ASU is required for annual periods beginning after December 15, 2018, and interim periods therein. Early adoption is permitted. As the Company’s future minimum lease commitments as of December 31, 2017 are approximately $0.6 million, the Company believes the future adoption of this ASU will not have a material impact on its financial position, results of operations or cash flows. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting Throughout the year ended December 31, 2016, the FASB issued a number of ASUs which provide further clarification to ASU No. 2014-09, Revenue (Topic 606): Revenue from Contracts with Customers In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718)-Scope of Modification Accounting, required f r o d g n e 5 20

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Cash and Cash Equivalents	Cash and cash equivalents are comprised of the following (in thousands): December 31, 2017 2016 Cash $ 15,200 $ 13,485 Money market funds 169,282 161,146 $ 184,482 $ 174,631
Computation of Basic and Diluted Income (Loss) Per Share	The following table sets forth the computation of basic and diluted income (loss) per share (in thousands, except share and per share data): Year ended December 31, 2017 2016 2015 Net income (loss) attributable to Pendrell $ 19,060 $ 17,763 $ (109,680 ) Weighted average common shares outstanding 250,428 268,276 267,136 Less: weighted average unvested restricted stock awards (562 ) (687 ) (1,429 ) Shares used for computation of basic income (loss) per share 249,866 267,589 265,707 Add back: weighted average unvested restricted stock awards and units 6,948 9,329 — Shares used for computation of diluted income (loss) per share (1) 256,814 276,918 265,707 Basic income (loss) per share attributable to Pendrell $ 76.28 $ 66.38 $ (412.79 ) Diluted income (loss) per share attributable to Pendrell $ 74.22 $ 64.15 $ (412.79 ) (1) Stock options, restricted stock awards and units totaling 12,500, 13,053 and 27,847 for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from the calculation of diluted income (loss) per share as their inclusion was anti-dilutive.

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets and Related Amortization	The following table presents details of the Company’s intangible assets and related amortization (in thousands): December 31, 2017 December 31, 2016 Patent cost $ 58,553 $ 65,796 Patent accumulated amortization (56,224 ) (61,080 ) Intangible assets, net $ 2,329 $ 4,716
Summary of Amortization Expense Related to Purchased Intangible Assets	Amortization expense related to purchased intangible assets, reported as amortization of intangible assets in the consolidated statements of operations, for the years ended December 31, 2017, 2016 and 2015 were as follows (in thousands): Year ended December 31, 2017 2016 2015 Amortization of intangible assets $ 2,345 $ 9,498 $ 13,939
Summary of Costs Associated with Patents Sold	Costs associated with patents sold during the years ended December 31, 2017, 2016 and 2015 were as follows (in thousands): Year ended December 31, 2017 2016 2015 Cost of patents sold $ — $ — $ 138
Summary of Cost Associated with Abandonment and Disposition of Patents	Costs associated with the abandonment of patents, including any remaining net book value, are included in “patent administration and related costs” in the Company’s consolidated statements of operations and were as follows for the years ended December 31, 2017, 2016 and 2015 (in thousands): Year ended December 31, 2017 2016 2015 Cost associated with the abandonment and/or disposition of patents $ 41 $ 163 $ 958

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Payables And Accruals [Abstract]
Summary of Accrued Expenses	The following table summarizes accrued expenses (in thousands): December 31, 2017 December 31, 2016 Accrued payroll and related expenses $ 1,915 $ 1,134 Accrued legal, professional and other expenses 782 538 Accrued revenue share obligations 6,100 4,606 $ 8,797 $ 6,278

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Rental Expense	Total rental expense included in general and administrative expenses in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Rent expense $ 282 $ 245 $ 793
Future Minimum Payment Under Lease Agreements	As of December 31, 2017, future minimum payments under the Company’s lease agreements were as follows (in thousands): Operating leases 2018 $ 348 2019 205 Total minimum payments $ 553

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense Included in Consolidated Statements of Operations	Stock-based compensation expense included in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Stock options $ 884 $ 1,193 $ 2,236 Restricted stock awards (1) 2,538 2,231 2,271 Total stock-based compensation expense $ 3,422 $ 3,424 $ 4,507 ( 1 ) Stock-based compensation expense for the year ended December 31, 2015 includes $0.2 million of expense related to 250 Class A common stock restricted stock awards that were required to be treated as a liability. The Company settled the related liability with a $2.5 million payment in April 2015 and no further expense has been incurred.
Estimated Weighted Average Fair Value of Stock Options Granted Using Black-Scholes Model	The weighted average fair value of stock options granted during the years ended December 31, 2017, 2016 and 2015 was estimated using the Black-Scholes Model with the following assumptions: Year ended December 31, 2017 2016 2015 Weighted average expected volatility 49 % 53 % 48 % Weighted average risk-free interest rate 2.0 % 1.2 % 1.9 % Expected dividend yield 0 % 0 % 0 % Weighted average expected term in years 5.5 5.5 6.0 Weighted average estimated fair value per option granted $ 319.70 $ 332.00 $ 470.00
Stock Option Activity	The Company’s stock option activity for the year ended December 31, 2017 is summarized as follows: Number of options Weighted average exercise price Weighted average remaining life (in years) Outstanding at December 31, 2016 13,045 $ 1,569.84 Granted (1) 240 687.00 Forfeited (785 ) 2574.43 Outstanding at December 31, 2017 (2) 12,500 $ 1,489.80 6.04 Exercisable at December 31, 2017 (2) 9,552 $ 1,547.53 5.60 Vested and expected to vest at December 31, 2017 (2) 12,500 $ 1,489.80 6.04 (1) All options granted were to members of the Company’s board of directors. (2) Aggregate intrinsic value represents the amount by which the market value of the underlying stock exceeded the exercise price of outstanding options, before applicable income taxes and represents the amount optionees would have realized if all in-the-money options had been exercised on December 31, 2017. As of December 31, 2017, the aggregate intrinsic values of stock options outstanding, exercisable, and vested and expected to vest were all zero as the closing stock price of the Company’s stock was lower than the exercise prices of its outstanding options.
Summary of Significant Ranges of Outstanding and Exercisable Stock Options	The following table summarizes significant ranges of outstanding and exercisable stock options as of December 31, 2017: Outstanding stock options Exercisable stock options Range of exercise prices Number of options Weighted average exercise price Weighted average remaining life (in years) Number of options Weighted average exercise price $ 687—$1,255 2,570 $ 1,039 5.57 2,330 $ 1,076 $1,256—$1,325 1,925 1,304 7.21 1,522 1,302 $1,326—$1,405 4,000 1,340 7.46 2,000 1,340 $1,406—$1,845 1,872 1,562 4.96 1,567 1,568 $1,846—$2,780 2,133 2,418 3.87 2,133 2,418 12,500 $ 1,490 6.04 9,552 $ 1,548
Restricted Stock Award Activity	The Company’s restricted stock award activity for the year ended December 31, 2017 is summarized as follows: Number of restricted stock awards Weighted average grant date fair value Unvested—December 31, 2016 8,907 $ 822.67 Granted (1) 625 681.67 Vested (2,719 ) 817.39 Forfeited (162 ) 522.93 Unvested—December 31, 2017 (2) 6,651 $ 904.00 (1) Represents shares issued to the Company’s Board of Directors as compensation for service. These awards have a grant date fair value of $0.4 million and vest upon issuance. ( 2 ) 2,089 of the awards outstanding at December 31, 2017 will either vest or expire in 2018, with the balance either vesting or expiring in 2019.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Tax Benefit (Expense)	The Company’s income tax benefit (expense) for the years ended December 31, 2017, 2016 and 2015 consists of the following (in thousands): Year ended December 31, 2017 2016 2015 United States—current $ 2,182 $ — $ — United States—deferred — — 1,497 Foreign—current (72 ) — (4,128 ) Income tax benefit (expense) $ 2,110 $ — $ (2,631 )
Reconciliation of Federal Statutory Income Tax Rate of 34% to Effective Income Tax Rate	A reconciliation of the 2017, 2016 and 2015 federal statutory income tax rate of 34% to the Company’s effective income tax rate is as follows: Year ended December 31, 2017 2016 2015 Statutory tax rate 34.00 % 34.00 % 34.00 % Change in valuation allowance (1,862.16 ) (59.30 ) (22.59 ) Impact of change in tax law 1,821.35 — — State income taxes (8.01 ) — — Foreign withholding taxes 0.26 — (2.37 ) Goodwill impairment — — (6.07 ) Stock-based compensation 1.42 10.24 (3.23 ) Loss on sale of subsidiary — 13.70 — Other 1.24 1.36 (2.03 ) Effective tax rate (11.90 )% 0 % (2.29 )%
Significant Components of Net Deferred Tax Assets and Liabilities	The significant components of the Company’s net deferred tax assets are as follows (in thousands): December 31, 2017 December 31, 2016 Net deferred tax assets: Net operating losses $ 624,984 $ 941,163 Basis difference in Liquidating Trust 10,380 16,955 Accrued expenses and other 5,083 12,336 Total deferred tax assets 640,447 970,454 Valuation allowance (640,447 ) (970,454 ) Net deferred tax assets $ — $ —
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): December 31, 2017 2016 2015 Beginning of period $ 15,323 $ 15,594 $ 5,132 Additions for tax positions taken during the current period — — 10,462 Reductions periods (2,950 ) — — Settlements with tax authorities (2,182 ) — — Exchange rate fluctuations 1,352 (271 ) — End of period $ 11,543 $ 15,323 $ 15,594

Employee Benefits (Tables)

Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Expense Related to Contributions under Defined Contribution Retirement Included in General and Administrative Expense	Expense related to contributions by the Company under the defined contribution retirement plan included in general and administrative expenses in the Company’s consolidated statements of operations for the years ended December 31, 2017, 2016 and 2015 was as follows (in thousands): Year ended December 31, 2017 2016 2015 Defined contribution expenses $ 65 $ 80 $ 201

Unaudited Quarterly Financial D

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Results	Unaudited quarterly results were as follows (in thousands, except per share data): Three months ended March 31, June 30, September 30, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 Revenue $ — $ 13,500 $ 35,122 $ 45,003 $ 5,443 $ — $ 2,209 $ 515 Operating income (loss) (8,064 ) 4,928 24,462 21,103 1,918 (5,501 ) (2,165 ) (5,313 ) Net income (loss) (7,783 ) 7,110 24,203 21,257 2,343 (5,341 ) 1,093 (5,077 ) Net income (loss) attributable to Pendrell (7,759 ) 6,565 24,228 21,420 1,713 (5,254 ) 878 (4,968 ) Basic income (loss) per share attributable to Pendrell $ (29.33 ) $ 24.58 $ 98.49 $ 80.07 $ 6.96 $ (19.62 ) $ 3.61 $ (18.54 ) Diluted income (loss) per share attributable to Pendrell $ (29.33 ) $ 23.72 $ 95.80 $ 77.33 $ 6.78 $ (19.62 ) $ 3.51 $ (18.54 )

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Jun. 30, 2017Stockholder	Sep. 30, 2016	Dec. 31, 2017USD ($)Segment	Dec. 31, 2015USD ($)	Jan. 01, 2017USD ($)	Dec. 31, 2016USD ($)	Feb. 28, 2015
Significant Accounting Policies [Line Items]
Loans to subsidiaries			$ 31,800,000
Reverse stock split ratio		0.1
Number of operating and reporting segments | Segment			1
Allowance for doubtful accounts			$ 0			$ 0
Impairment of intangibles and goodwill				$ 103,499,000
Future minimum lease commitments			553,000
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Future minimum lease commitments			$ 600,000
Software
Significant Accounting Policies [Line Items]
Property in Service, estimated useful life			3 years
Property in service, estimated useful lives, description			Software is depreciated over the shorter of its contractual license period or three years.
Maximum | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Property in Service, estimated useful life			5 years
Minimum [Member] | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Property in Service, estimated useful life			3 years
Class A Stock and Class B common stock
Significant Accounting Policies [Line Items]
Reverse stock split ratio	0.01
Description of reverse stock split			At the Company’s annual meeting of shareholders in June 2017, the Company’s shareholders approved a 1-for-100 reverse stock split of the Company’s Class A Stock and Class B common stock that was implemented on November 30, 2017 (the "2017 Reverse Split"). The 2017 Reverse Split reduced the Company’s number of record shareholders to less than 300, which allowed it to (i) terminate the Company’s Nasdaq listing, effective December 15, 2017, (ii) file to de-register the Company’s Class A Stock under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which was filed on December 26, 2017; and (iii) cease to be a reporting company under the Exchange Act after the Company’s notice of de-registration is effective, which will be no later than March 26, 2018.In September 2016, the Company consummated a 1-for-10 reverse stock split (the “2016 Reverse Split”) to remediate a stock price deficiency as required by Nasdaq’s continued listing requirements.
Class A Stock and Class B common stock | Maximum
Significant Accounting Policies [Line Items]
Number of record shareholders after Reverse Split | Stockholder	300
Additional Paid-in Capital | Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Adjustment to retained earnings and additional paid in capital due to change in accounting for forfeitures			$ 200,000		$ 200,000
Provitro Biosciences LLC
Significant Accounting Policies [Line Items]
Ownership Percentage By Parent							100.00%
ContentGuard
Significant Accounting Policies [Line Items]
Sale of ownership percentage held in subsidiary	9.00%
Ownership Percentage By Parent	81.10%

Summary of Cash and Cash Equiva

Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 184,482	$ 174,631	$ 162,457	$ 168,793
Cash
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	15,200	13,485
Money Market Funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 169,282	$ 161,146

Computation of Basic and Dilute

Computation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income (loss) attributable to Pendrell		$ 878	$ 1,713	$ 24,228	$ (7,759)	$ (4,968)	$ (5,254)	$ 21,420	$ 6,565	$ 19,060	$ 17,763	$ (109,680)
Weighted average common shares outstanding										250,428	268,276	267,136
Less: weighted average unvested restricted stock awards										(562)	(687)	(1,429)
Shares used for computation of basic income (loss) per share										249,866	267,589	265,707
Add back: weighted average unvested restricted stock awards and units										6,948	9,329
Shares used for computation of diluted income (loss) per share	[1]									256,814	276,918	265,707
Basic income (loss) per share attributable to Pendrell		$ 3.61	$ 6.96	$ 98.49	$ (29.33)	$ (18.54)	$ (19.62)	$ 80.07	$ 24.58	$ 76.28	$ 66.38	$ (412.79)
Diluted income (loss) per share attributable to Pendrell		$ 3.51	$ 6.78	$ 95.80	$ (29.33)	$ (18.54)	$ (19.62)	$ 77.33	$ 23.72	$ 74.22	$ 64.15	$ (412.79)
[1]	Stock options, restricted stock awards and units totaling 12,500, 13,053 and 27,847 for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from the calculation of diluted income (loss) per share as their inclusion was anti-dilutive.

Computation of Basic and Dilu35

Computation of Basic and Diluted Income (Loss) Per Share (Parenthetical) (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Securities (Stock options, restricted stock awards and units) that were excluded from the calculation of diluted income (loss) per share	12,500	13,053	27,847

Provitro - Additional Informati

Provitro - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended				12 Months Ended
	Jan. 31, 2017	Aug. 31, 2016	Jan. 31, 2016	Sep. 30, 2015	Dec. 31, 2015	Feb. 28, 2015	Feb. 28, 2013
Business Acquisition [Line Items]
Proceeds associated with disposition of property					$ 109
Provitro Biosciences LLC
Business Acquisition [Line Items]
Percentage of business acquisition interest							68.75%
Ownership Percentage By Parent						100.00%
Proceeds associated with disposition of property	$ 600	$ 900	$ 400	$ 100
Provitro Biosciences LLC | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Considerations paid and payable under the sale of assets				$ 2,000

Accounts Receivable (Current 37

Accounts Receivable (Current and Non-current) - Additional Information (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts		$ 0	$ 0
Non-current accounts receivable		$ 1,309,000	16,555,000
Scenario, Forecast
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-current accounts receivable	$ 1,300,000
Toshiba Memory Corporation
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts			$ 0

Intangible Assets and Goodwil38

Intangible Assets and Goodwill - Additional Information (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2017Patent	Dec. 31, 2016Patent	Dec. 31, 2015USD ($)
Impairment of Intangible Assets [Line Items]
Non-cash impairment charge on infinite and finite lived intangible assets	$ 82.3			$ 82.3
Impairment of goodwill	$ 21.2
Cost incurred to enhance the existing patent				$ 2
Number of patents purchased | Patent		0	0
Number of patents sold | Patent			0
Patents
Impairment of Intangible Assets [Line Items]
Finite lived intangible asset, fully amortized date		Dec. 31, 2018

Intangible Assets and Related A

Intangible Assets and Related Amortization (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Patent accumulated amortization	$ (56,224)	$ (61,080)
Intangible assets, net	2,329	4,716
Patents
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Patent cost	58,553	65,796
Patent accumulated amortization	(56,224)	(61,080)
Intangible assets, net	$ 2,329	$ 4,716

Summary of Amortization Expense

Summary of Amortization Expense Related to Purchased Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 2,345	$ 9,498	$ 13,939

Summary of Costs Associated wit

Summary of Costs Associated with Patents Sold (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Cost of patents sold	$ 0	$ 0	$ 138

Summary of Cost Associated with

Summary of Cost Associated with Abandonment and Disposition of Patents (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Loss associated with the abandonment and/or disposition of patents	$ 41	$ 163	$ 958

Summary of Accrued Expenses (De

Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued payroll and related expenses	$ 1,915	$ 1,134
Accrued legal, professional and other expenses	782	538
Accrued revenue share obligations	6,100	4,606
Accrued expenses	$ 8,797	$ 6,278

Rent Expense (Detail)

Rent Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Rent expense	$ 282	$ 245	$ 793

Future Minimum Payment under Le

Future Minimum Payment under Lease Agreements (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 348
2,019	205
Total minimum payments	$ 553

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail)	Mar. 09, 2017$ / sharesshares	Dec. 31, 2016USD ($)	Nov. 14, 2012shares	Dec. 31, 2017USD ($)Voter / sharesClass$ / sharesshares	Dec. 31, 2017USD ($)Voter / sharesClass$ / sharesshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	Nov. 30, 2017$ / shares	Jan. 01, 2017USD ($)
Class Of Stock [Line Items]
Number of classes of common stock | Class				2	2
Dividend, Declared date					Nov. 30, 2017
Dividend, Declared per share | $ / shares								$ 12.32
Dividend, Paid date					Dec. 27, 2017
Dividend, Date of record					Dec. 15, 2017
Estimated forfeiture rate						5.00%	5.00%
Stock-based compensation cost to be expensed in 2018 related to unvested stock-based awards | $				$ 2,100,000	$ 2,100,000
Stock-based compensation cost to be expensed in future years related to unvested stock-based awards | $				$ 2,100,000	2,100,000
Stock options vested, total fair value | $					$ 1,000,000	$ 2,000,000	$ 2,500,000
Repurchasing and/or cancelling value related to the vesting of the restricted stock awards | $						$ 40,000	$ 140,000
Directors Consultants And Employee Stock Option
Class Of Stock [Line Items]
Stock options expiration period					10 years
Directors Consultants And Employee Stock Option | Stock options issued as Board of Director compensation
Class Of Stock [Line Items]
Stock options exercisable period					1 year
Directors Consultants And Employee Stock Option | Termination Of Employment
Class Of Stock [Line Items]
Stock options expiration period					3 months
Stock Appreciation Rights
Class Of Stock [Line Items]
Number of rights outstanding | shares				0	0
Restricted stock awards
Class Of Stock [Line Items]
Stock-awards vested | shares					2,719
Performance- based | Performance Based Stock Option
Class Of Stock [Line Items]
Stock options, Vest upon achievement of performance milestones | shares							500
Performance- based | Performance-based
Class Of Stock [Line Items]
Restricted stock awards, Vest upon achievement of performance milestones | shares							1,000
Service- based | Directors Consultants And Employee Stock Option
Class Of Stock [Line Items]
Stock options exercisable period					4 years
Service and performance- based | Restricted stock awards
Class Of Stock [Line Items]
Stock-awards vested | shares						2,094
Repurchasing and/or cancelling shares related to the vesting of the restricted stock awards | shares						24
Repurchasing and/or cancelling value related to the vesting of the restricted stock awards | $						$ 17,000
Additional paid-in capital
Class Of Stock [Line Items]
Repurchasing and/or cancelling value related to the vesting of the restricted stock awards | $						$ 40,000	$ 131,000
Accumulated deficit
Class Of Stock [Line Items]
Repurchasing and/or cancelling value related to the vesting of the restricted stock awards | $							$ 8,000
Accounting Standards Update 2016-09 | Additional paid-in capital
Class Of Stock [Line Items]
Adjustment to retained earnings and additional paid in capital due to change in accounting for forfeitures | $				$ 200,000	$ 200,000				$ 200,000
Accounting Standards Update 2016-09 | Accumulated deficit
Class Of Stock [Line Items]
Adjustment to retained earnings and additional paid in capital due to change in accounting for forfeitures | $									$ 200,000
2000 Plan
Class Of Stock [Line Items]
Number of additional awards will be granted | shares			0
Equity Incentive Plan Twenty Twelve
Class Of Stock [Line Items]
Maximum number of shares to be issued | shares				37,952	37,952
Shares reserved and available for grant | shares				24,743	24,743
Principal Owner
Class Of Stock [Line Items]
Eagle River's economic interest percentage				37.40%	37.40%
Eagle River's voting interest percentage				67.60%	67.60%
Class A common stock
Class Of Stock [Line Items]
Number of vote entitled per share | Voter / shares				1	1
Number of common stock redeemed | shares				6,150
Common stock, average redemption price per share | $ / shares				$ 606	$ 606
Dividends, Cash | $		$ 0
Class A common stock | Crusader
Class Of Stock [Line Items]
Number of common stock redeemed | shares	24,328
Common stock, redemption price per share | $ / shares	$ 655
Class B common stock
Class Of Stock [Line Items]
Number of vote entitled per share | Voter / shares				10	10
Common Stock, Conversion Basis					Each share of Class B common stock is convertible into one share of Class A common stock.
Dividends, Cash | $		$ 0

Stock-Based Compensation Expens

Stock-Based Compensation Expense Included in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation		$ 3,422	$ 3,424	$ 4,507
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation		884	1,193	2,236
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	[1]	$ 2,538	$ 2,231	$ 2,271
[1]	Stock-based compensation expense for the year ended December 31, 2015 includes $0.2 million of expense related to 250 Class A common stock restricted stock awards that were required to be treated as a liability. The Company settled the related liability with a $2.5 million payment in April 2015 and no further expense has been incurred

Stock-Based Compensation Expe48

Stock-Based Compensation Expense Included in Consolidated Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation		$ 3,422	$ 3,424	$ 4,507
Restricted stock awards liability
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation				$ 200
Restricted stock awards accounted for liability awards				250
Payment to settle related liability	$ 2,500

Estimated Weighted Average Fair

Estimated Weighted Average Fair Value of Stock Options Granted Using Black-Scholes Model (Detail) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average expected volatility	49.00%	53.00%	48.00%
Weighted average risk-free interest rate	2.00%	1.20%	1.90%
Expected dividend yield	0.00%	0.00%	0.00%
Weighted average expected term in years	5 years 6 months	5 years 6 months	6 years
Weighted average estimated fair value per option granted	$ 319.70	$ 332	$ 470

Stock Option Activity (Detail)

Stock Option Activity (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Number of options
Outstanding at beginning of period | shares	13,045
Granted | shares	240	[1]
Forfeited | shares	(785)
Outstanding at end of period | shares	12,500	[2]
Exercisable at end of period | shares	9,552	[2]
Vested and expected to vest at end of period | shares	12,500	[2]
Weighted average exercise price
Outstanding at beginning of period | $ / shares	$ 1,569.84
Granted | $ / shares	687	[1]
Forfeited | $ / shares	2,574.43
Outstanding at end of period | $ / shares	1,489.80	[2]
Exercisable at end of period | $ / shares	1,547.53	[2]
Vested and expected to vest at end of period | $ / shares	$ 1,489.80	[2]
Weighted average remaining life (in years)
Outstanding at end of period	6 years 14 days	[2]
Exercisable at end of period	5 years 7 months 6 days	[2]
Vested and expected to vest at end of period	6 years 14 days	[2]
[1]	All options granted were to members of the Company’s board of directors.
[2]	Aggregate intrinsic value represents the amount by which the market value of the underlying stock exceeded the exercise price of outstanding options, before applicable income taxes and represents the amount optionees would have realized if all in-the-money options had been exercised on December 31, 2017. As of December 31, 2017, the aggregate intrinsic values of stock options outstanding, exercisable, and vested and expected to vest were all zero as the closing stock price of the Company’s stock was lower than the exercise prices of its outstanding options.

Stock Option Activity (Parenthe

Stock Option Activity (Parenthetical) (Detail) - Stock options	Dec. 31, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic values of stock options outstanding	$ 0
Aggregate intrinsic values of stock options exercisable	0
Aggregate intrinsic values of stock vested and expected to vest	$ 0

Summary of Significant Ranges o

Summary of Significant Ranges of Outstanding and Exercisable Stock Options (Detail) - $ / shares		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock options, Number of options		12,500	[1]	13,045
Outstanding stock options, Weighted average exercise price		$ 1,489.80	[1]	$ 1,569.84
Outstanding at end of period	[1]	6 years 14 days
Exercisable stock options, Number of options	[1]	9,552
Exercisable stock options, Weighted average exercise price	[1]	$ 1,547.53
$ 687—$1,255
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit		687
Range of exercise prices, upper limit		$ 1,255
Outstanding stock options, Number of options		2,570
Outstanding stock options, Weighted average exercise price		$ 1,039
Outstanding at end of period		5 years 6 months 25 days
Exercisable stock options, Number of options		2,330
Exercisable stock options, Weighted average exercise price		$ 1,076
$1,256—$1,325
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit		1,256
Range of exercise prices, upper limit		$ 1,325
Outstanding stock options, Number of options		1,925
Outstanding stock options, Weighted average exercise price		$ 1,304
Outstanding at end of period		7 years 2 months 15 days
Exercisable stock options, Number of options		1,522
Exercisable stock options, Weighted average exercise price		$ 1,302
$1,326—$1,405
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit		1,326
Range of exercise prices, upper limit		$ 1,405
Outstanding stock options, Number of options		4,000
Outstanding stock options, Weighted average exercise price		$ 1,340
Outstanding at end of period		7 years 5 months 15 days
Exercisable stock options, Number of options		2,000
Exercisable stock options, Weighted average exercise price		$ 1,340
$1,406—$1,845
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit		1,406
Range of exercise prices, upper limit		$ 1,845
Outstanding stock options, Number of options		1,872
Outstanding stock options, Weighted average exercise price		$ 1,562
Outstanding at end of period		4 years 11 months 15 days
Exercisable stock options, Number of options		1,567
Exercisable stock options, Weighted average exercise price		$ 1,568
$1,846—$2,780
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit		1,846
Range of exercise prices, upper limit		$ 2,780
Outstanding stock options, Number of options		2,133
Outstanding stock options, Weighted average exercise price		$ 2,418
Outstanding at end of period		3 years 10 months 13 days
Exercisable stock options, Number of options		2,133
Exercisable stock options, Weighted average exercise price		$ 2,418
[1]	Aggregate intrinsic value represents the amount by which the market value of the underlying stock exceeded the exercise price of outstanding options, before applicable income taxes and represents the amount optionees would have realized if all in-the-money options had been exercised on December 31, 2017. As of December 31, 2017, the aggregate intrinsic values of stock options outstanding, exercisable, and vested and expected to vest were all zero as the closing stock price of the Company’s stock was lower than the exercise prices of its outstanding options.

Restricted Stock Activity (Deta

Restricted Stock Activity (Detail) - Restricted stock awards	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Number of restricted stock awards
Unvested Beginning Balance | shares	8,907
Granted | shares	625	[1]
Vested | shares	(2,719)
Forfeited | shares	(162)
Unvested Ending Balance | shares	6,651	[2]
Weighted average grant date fair value
Unvested Beginning Balance | $ / shares	$ 822.67
Granted | $ / shares	681.67	[1]
Vested | $ / shares	817.39
Forfeited | $ / shares	522.93
Unvested Ending Balance | $ / shares	$ 904
[1]	Represents shares issued to the Company’s Board of Directors as compensation for service. These awards have a grant date fair value of $0.4 million and vest upon issuance.
[2]	2,089 of the awards outstanding at December 31, 2017 will either vest or expire in 2018, with the balance either vesting or expiring in 2019.

Restricted Stock Activity (Pare

Restricted Stock Activity (Parenthetical) (Detail) - Restricted stock awards - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding that will either vest or expire in the next 12 months		2,089
Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards grant date fair value	$ 0.4

Contract Termination Costs - Ad

Contract Termination Costs - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Contract Termination Costs [Abstract]
Up-front payment for memory patents	$ 3.2

Gain on Contingencies - Additio

Gain on Contingencies - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)Payment
Gain Contingencies [Line Items]
Number of contingent scheduled payments received | Payment			2
Number of contingent scheduled payments | Payment			3
Gain on contingencies		$ 2,047	$ 6,095
Ovidian
Gain Contingencies [Line Items]
Gain on release of a tax indemnification liability			500
J&J Arbitration
Gain Contingencies [Line Items]
Gain on contingencies	$ 1,600
First and Second Scheduled MEO Sale Payments
Gain Contingencies [Line Items]
Gain on contingencies			$ 3,900
Final Scheduled MEO Sale Payments
Gain Contingencies [Line Items]
Gain on contingencies		$ 2,000

Income Tax Benefit (Expense) (D

Income Tax Benefit (Expense) (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States—current		$ 2,182,000
United States—deferred				$ 1,497,000
Foreign—current		(72,000)	$ 0	(4,128,000)
Income tax benefit (expense)	$ 2,100,000	$ 2,110,000		$ (2,631,000)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	Dec. 27, 2017USD ($)	Dec. 31, 2017USD ($)Stockholder	Dec. 31, 2017USD ($)Stockholder	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Income Tax Contingency [Line Items]
Income tax benefit (expense)		$ 2,100,000	$ 2,110,000		$ (2,631,000)
Foreign income tax provision			$ 72,000	$ 0	4,128,000
Federal tax benefit (expense)					$ 1,497,000
Federal income tax provision				$ 0
Statutory tax rate			34.00%	34.00%	34.00%
Reduction in net deferred tax assets			$ (323,200,000)
Net operating loss carry forwards		$ 2,500,000,000	$ 2,500,000,000
Net operating loss carry forwards, year expiration begins			2,025
Net operating loss carry forwards, year expiration			2,032
Income tax description			Broadly, the Company will have a Tax Ownership Change if, over a three-year testing period, the portion of all stock of the Company, by value, owned by one or more 5% shareholder increases by more than 50 percentage points. For purposes of this test, shareholders that own less than 5% of the stock of the Company are aggregated into one or more separate “public groups”, each of which is treated as a 5% shareholder.
Tax ownership change testing period, year			3 years
Tax ownership change, number of shareholders | Stockholder			1
Tax ownership change, shareholder ownership percentage		5.00%	5.00%
Tax ownership change, shareholder ownership percentage increase		50.00%	50.00%
Unrecognized tax benefit		$ 11,543,000	$ 11,543,000	$ 15,323,000	$ 15,594,000	$ 5,132,000
Income tax refund			2,200,000
Reduction in unrecognized tax benefits			$ (3,000,000)
Personal holding company determination, number of shareholders limit | Stockholder		5	5
Ownership percentage of individual shareholders in a personal holding company			50.00%
Percentage of adjusted ordinary gross income pertaining to individual shareholders			60.00%
Personal holding company tax rate on net personal holding company income			20.00%
Dividend payment made to shareholders	$ 3,000,000	$ 3,000,000
Tax Benefits Preservation Plan trigger, ownership percentage			4.90%
Additional percentage of beneficial interest acquired to trigger tax benefit preservation plan			0.50%
Tax Benefits Preservation Plan			Holders of 4.9% or more of the Company’s securities outstanding as of the close of business on January 29, 2010 will not trigger the Tax Benefits Plan so long as they do not (i) acquire additional securities constituting one-half of one percent (0.5%) or more of the Company’s securities outstanding as of the date of the Tax Benefits Plan (as adjusted to reflect any stock splits, subdivisions and the like), or (ii) fall under 4.9% ownership of the Company’s securities and then re-acquire securities that increase their ownership to 4.9% or more of the Company’s securities. The Board of Directors may exempt certain persons whose acquisition of securities is determined by the Board of Directors not to jeopardize the Company’s tax benefits or to otherwise be in the best interest of the Company and its shareholders. The Board of Directors may also exempt certain transactions.
Accounting Standards Update 2016-09
Income Tax Contingency [Line Items]
Increase in net operating loss			$ 300,000
California Franchise Tax Board
Income Tax Contingency [Line Items]
Net operating loss carry forwards		$ 1,300,000,000	$ 1,300,000,000
Net operating loss carry forwards, year expiration			2,028
Maximum
Income Tax Contingency [Line Items]
Statutory tax rate			35.00%
Tax Year 2018 | Maximum
Income Tax Contingency [Line Items]
Statutory tax rate			21.00%

Reconciliation of Federal Statu

Reconciliation of Federal Statutory Income Tax Rate of 34% to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory tax rate	34.00%	34.00%	34.00%
Change in valuation allowance	(1862.16%)	(59.30%)	(22.59%)
Impact of change in tax law	1821.35%
State income taxes	(8.01%)
Foreign withholding taxes	0.26%		(2.37%)
Goodwill impairment			(6.07%)
Stock-based compensation	1.42%	10.24%	(3.23%)
Loss on sale of subsidiary		13.70%
Other	1.24%	1.36%	(2.03%)
Effective tax rate	(11.90%)	0.00%	(2.29%)

Significant Components of Net D

Significant Components of Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net operating losses	$ 624,984	$ 941,163
Basis difference in Liquidating Trust	10,380	16,955
Accrued expenses and other	5,083	12,336
Total deferred tax assets	640,447	970,454
Valuation allowance	$ (640,447)	$ (970,454)

Reconciliation of Beginning and

Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Total liability, Beginning of period	$ 15,323	$ 15,594	$ 5,132
Additions for tax positions taken during the current period			10,462
Reductions for tax positions taken during prior periods	(2,950)
Settlements with tax authorities	(2,182)
Exchange rate fluctuations	1,352	(271)
Total liability, End of period	$ 11,543	$ 15,323	$ 15,594

Expense Related to Contribution

Expense Related to Contributions under Defined Contribution Retirement Included in General and Administrative Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Postemployment Benefits [Abstract]
Defined contribution expenses	$ 65	$ 80	$ 201

Related Parties - Additional In

Related Parties - Additional Information (Detail) - Principal Owner	Dec. 31, 2017
Related Party Transaction [Line Items]
Eagle River's economic interest percentage	37.40%
Eagle River's voting interest percentage	67.60%

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 27, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Reversal of accrued tax expense benefit		$ 600
Income tax benefit (expense)		2,100	$ 2,110	$ (2,631)
Dividend payment made to shareholders	$ 3,000	$ 3,000

Unaudited Quarterly Results (De

Unaudited Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 2,209	$ 5,443	$ 35,122		$ 515		$ 45,003	$ 13,500	$ 42,774	$ 59,018	$ 43,519
Operating income (loss)	(2,165)	1,918	24,462	$ (8,064)	(5,313)	$ (5,501)	21,103	4,928	16,151	15,217	(121,135)
Net income (loss)	1,093	2,343	24,203	(7,783)	(5,077)	(5,341)	21,257	7,110	19,856	17,949	(117,582)
Net income (loss) attributable to Pendrell	$ 878	$ 1,713	$ 24,228	$ (7,759)	$ (4,968)	$ (5,254)	$ 21,420	$ 6,565	$ 19,060	$ 17,763	$ (109,680)
Basic income (loss) per share attributable to Pendrell	$ 3.61	$ 6.96	$ 98.49	$ (29.33)	$ (18.54)	$ (19.62)	$ 80.07	$ 24.58	$ 76.28	$ 66.38	$ (412.79)
Diluted income (loss) per share attributable to Pendrell	$ 3.51	$ 6.78	$ 95.80	$ (29.33)	$ (18.54)	$ (19.62)	$ 77.33	$ 23.72	$ 74.22	$ 64.15	$ (412.79)

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
		Jan. 23, 2018	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015	Feb. 16, 2018
Subsequent Event [Line Items]
Outstanding options				12,500	[1]	13,045
Stock-based compensation				$ 3,422		$ 3,424	$ 4,507
Restricted stock awards
Subsequent Event [Line Items]
Outstanding restricted stock				86
Stock-based compensation	[2]			$ 2,538		$ 2,231	$ 2,271
Subsequent Event
Subsequent Event [Line Items]
Outstanding options								3,184
Subsequent Event | Scenario, Forecast
Subsequent Event [Line Items]
Stock-based compensation			$ 700
Subsequent Event | Stock Options and Restricted Stock | Tranche One
Subsequent Event [Line Items]
Stock options and restricted stock vesting, percentage		25.00%
Stock options and restricted stock vesting date		Aug. 15, 2018
Subsequent Event | Stock Options and Restricted Stock | Tranche Two
Subsequent Event [Line Items]
Stock options and restricted stock vesting, percentage		25.00%
Stock options and restricted stock vesting date		Aug. 15, 2019
Subsequent Event | Stock Options and Restricted Stock | Tranche Three
Subsequent Event [Line Items]
Stock options and restricted stock vesting, percentage		50.00%
Stock options and restricted stock vesting date		Aug. 15, 2020
[1]	Aggregate intrinsic value represents the amount by which the market value of the underlying stock exceeded the exercise price of outstanding options, before applicable income taxes and represents the amount optionees would have realized if all in-the-money options had been exercised on December 31, 2017. As of December 31, 2017, the aggregate intrinsic values of stock options outstanding, exercisable, and vested and expected to vest were all zero as the closing stock price of the Company’s stock was lower than the exercise prices of its outstanding options.
[2]	Stock-based compensation expense for the year ended December 31, 2015 includes $0.2 million of expense related to 250 Class A common stock restricted stock awards that were required to be treated as a liability. The Company settled the related liability with a $2.5 million payment in April 2015 and no further expense has been incurred