Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue
Laboratory service revenue	$ 57,646	$ 21,185	$ 106,009	$ 36,020
Cost of sales	17,991	10,097	34,972	19,156
Gross margin	39,655	11,088	71,037	16,864
Operating expenses:
Research and development	9,737	8,640	17,739	18,766
General and administrative	24,609	17,284	44,679	35,108
Sales and marketing	36,728	30,301	75,529	56,012
Total operating expenses	71,074	56,225	137,947	109,886
Loss from operations	(31,419)	(45,137)	(66,910)	(93,022)
Other income (expense)
Investment income	683	425	1,278	891
Interest expense	(54)	(53)	(104)	(107)
Total other income	629	372	1,174	784
Net loss	$ (30,790)	$ (44,765)	$ (65,736)	$ (92,238)
Net loss per share-basic and diluted (in dollars per share)	$ (0.27)	$ (0.46)	$ (0.59)	$ (0.95)
Weighted average common shares outstanding-basic and diluted (in shares)	112,847	97,902	111,721	97,578