Restatement and Revision of Quarterly Condensed Consolidated Financial Statements - Consolidated Statements of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								6 Months Ended	9 Months Ended			12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue
Revenue	$ 61,913	$ 56,915	$ 61,717	$ 65,777	$ 61,735	$ 59,187	$ 58,297	$ 48,384	$ 127,494	$ 184,409	$ 165,868		$ 246,322	$ 227,603	$ 231,201
Cost of revenue
Cost of product revenue		9,661	10,277	10,343		7,108			20,620	30,281	17,845		37,749	27,156	18,299
Cost of contract and other revenue		1,267	1,535	1,198		2,450			2,733	4,000	8,268		5,647	9,905	11,718
Amortization of acquired intangible assets, cost of revenue		4,336	4,336	4,344		3,016			8,680	13,016	10,686		17,352	14,314	23,684
Cost of revenue	13,451	15,264	16,148	15,885	14,576	12,574	13,027	11,198	32,033	47,297	36,799		60,748	51,375	53,701
Gross Profit	48,462	41,651	45,569	49,892	47,159	46,613	45,270	37,186	95,461	137,112	129,069		185,574	176,228	177,500
Operating expenses
Research and development		33,733	34,688	36,664		41,486			71,352	105,085	119,995		139,837	156,815	158,339
Sales, general and administrative		20,182	21,721	23,306		26,521			45,027	65,209	76,835		86,441	100,551	98,254
Amortization of acquired intangible assets		236	248	348		170			596	832	2,409		1,061	2,743	5,657
Restructuring and other charges		0	0	836		1,374			836	836	4,233		4,089	8,821	2,217
Impairment (recovery) of assets held for sale		0	0	0		(1,853)			0	0	15,137	$ 0
Change in fair value of earn-out liability		0	0	(1,800)		0			(1,800)	(1,800)	0	0	(1,800)	0	0
Total operating expenses	59,466	54,151	56,657	59,354	57,760	67,698	82,316	68,595	116,011	170,162	218,609		229,628	276,369	264,467
Operating loss	(11,004)	(12,500)	(11,088)	(9,462)	(10,601)	(21,085)	(37,046)	(31,409)	(20,550)	(33,050)	(89,540)		(44,054)	(100,141)	(86,967)
Interest income and other income (expense), net		3,554	4,688	6,443		6,751			11,131	14,685	21,136		17,855	27,445	32,621
Interest expense		(2,586)	(2,580)	(2,555)		(2,497)			(5,135)	(7,721)	(7,302)		(10,340)	(9,852)	(16,282)
Interest and other income (expense), net		968	2,108	3,888		4,254			5,996	6,964	13,834		7,515	17,593	16,339
Loss before income taxes		(11,532)	(8,980)	(5,574)		(16,831)			(14,554)	(26,086)	(75,706)		(36,539)	(82,548)	(70,628)
Provision for income taxes		1,205	160	965		(1,299)			1,125	2,330	3,382		3,932	3,416	87,329
Net loss	$ (12,055)	$ (12,737)	$ (9,140)	$ (6,539)	$ (6,876)	$ (15,532)	$ (36,980)	$ (26,576)	$ (15,679)	$ (28,416)	$ (79,088)	$ (155,939)	$ (40,471)	$ (85,964)	$ (157,957)
Net loss per share:
Basic (in dollars per share)	$ (0.11)	$ (0.11)	$ (0.08)	$ (0.06)	$ (0.06)	$ (0.14)	$ (0.33)	$ (0.24)	$ (0.14)	$ (0.25)	$ (0.71)		$ (0.36)	$ (0.77)	$ (1.46)
Diluted (in dollars per share)	$ (0.11)	$ (0.11)	$ (0.08)	$ (0.06)	$ (0.06)	$ (0.14)	$ (0.33)	$ (0.24)	$ (0.14)	$ (0.25)	$ (0.71)		$ (0.36)	$ (0.77)	$ (1.46)
Weighted-average shares used in per share calculations:
Basic (in shares)	112,706	113,828	113,572	112,907	111,883	111,315	110,875	109,692	113,240	113,437	110,633		113,254	110,948	108,450
Diluted (in shares)	112,706	113,828	113,572	112,907	111,883	111,315	110,875	109,692	113,240	113,437	110,633		113,254	110,948	108,450
Royalties
Revenue
Revenue		$ 16,602	$ 18,744	$ 21,482		$ 21,236			$ 40,226	$ 56,828	$ 73,139		$ 84,560	$ 94,361	$ 130,452
Product revenue
Revenue
Revenue		29,769	31,725	30,728		21,377			62,453	92,222	46,372		113,996	72,972	38,690
Contract and other revenue
Revenue
Revenue		$ 10,544	$ 11,248	$ 13,567		$ 16,574			$ 24,815	$ 35,359	$ 46,357		$ 47,766	$ 60,270	$ 62,059